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Search for "Grignard reagent" in Full Text gives 111 result(s) in Beilstein Journal of Organic Chemistry.
Total syntheses of highly oxidative Ryania diterpenoids facilitated by innovations in synthetic strategies
- Zhi-Qi Cao,
- Jin-Bao Qiao and
- Yu-Ming Zhao
Beilstein J. Org. Chem. 2025, 21, 2553–2570, doi:10.3762/bjoc.21.198
- route commenced from (−)-pulegone. After introducing oxidation states at C6 and C10 and installing an alkynyl group at C11, oxidative cleavage of a double bond yielded the key propargylic alcohol intermediate 66. This compound underwent a 1,2-addition with alkynyl Grignard reagent 67, and the resulting
Graphical Abstract
Scheme 1: Representative Ryania diterpenoids and their derivatives.
Scheme 2: Deslongchamps’s total synthesis of ryanodol (4).
Scheme 3: Deslongchamps’s total synthesis of 3-epi-ryanodol (5).
Scheme 4: Inoue’s total synthesis of ryanodol (4).
Scheme 5: Inoue’s total synthesis of ryanodine (1) from ryanodol (4).
Scheme 6: Inoue’s total synthesis of cinncassiol A (9), cinncassiol B (7), cinnzeylanol (6), and 3-epi-ryanod...
Scheme 7: Reisman’s total synthesis of (+)-ryanodol (4).
Scheme 8: Reisman’s total synthesis of (+)-ryanodine (1) and (+)-20-deoxyspiganthine (2).
Scheme 9: Micalizio’s formal total synthesis of ryanodol (4).
Scheme 10: Zhao’s total synthesis of garajonone (8).
Scheme 11: Zhao’s formal total synthesis of ryanodol (4) and ryanodine (1).
Ni-promoted reductive cyclization cascade enables a total synthesis of (+)-aglacin B
- Si-Chen Yao,
- Jing-Si Cao,
- Jian Xiao,
- Ya-Wen Wang and
- Yu Peng
Beilstein J. Org. Chem. 2025, 21, 2548–2552, doi:10.3762/bjoc.21.197
- asymmetric conjugate addition was carried out [20][21]. The in situ generated aryl–copper(I) species was obtained under the action of CuBr·Me2S with Grignard reagent 8, and then added to a THF solution of the α,β-unsaturated acyl oxazolidinone 7 at −48 °C. This reaction demonstrated an excellent
Graphical Abstract
Figure 1: The structures of aglacins A, B, C, and E.
Scheme 1: Retrosynthetic analysis of (+)-aglacin B (2).
Scheme 2: Synthesis of cyclization precursor 5.
Scheme 3: Synthesis of (+)-aglacin B (2).
Transformation of the cyclohexane ring to the cyclopentane fragment of biologically active compounds
- Natalya Akhmetdinova,
- Ilgiz Biktagirov and
- Liliya Kh. Faizullina
Beilstein J. Org. Chem. 2025, 21, 2416–2446, doi:10.3762/bjoc.21.185
- 50% yield. Banerjee et al. [95] demonstrated an alternative method for the synthesis of cyclopentane derivatives. The method included the cleavage of epoxides using Grignard reagents followed by ring contraction. Treatment of epoxide 212 with Grignard reagent through intermediates 213 and 214
- produced aldehyde 215, and further reaction of 215 with the Grignard reagent gave alcohol 216 (Scheme 38). A promising method for the contraction of cyclohexane rings is the semipinacol rearrangement. For the enantioselective total synthesis of (−)-citrinadin A (217) and (+)-citrinadin B (218), the authors
Graphical Abstract
Scheme 1: Ozonolysis–cyclization sequence in the synthesis of echinopine A (3).
Scheme 2: Ozonolysis–cyclization sequence in the synthesis of taiwaniaquinoids 7–12.
Figure 1: Iridoid skeleton.
Scheme 3: Ozonolysis–cyclization sequence in the synthesis of compounds 17a,b, 18 and 19 with iridoid topolog...
Scheme 4: Oxidation–aldol condensation sequence in the synthesis of compounds 21 and 23 with iridoid topology....
Scheme 5: Oxidation–aldol condensation sequence in the synthesis of compounds 29 and 30 with iridoid topology....
Scheme 6: Method for ring contraction in the absence of a double bond in a six-membered ring of triterpenoids....
Scheme 7: Oxidation–Dieckmann cyclization sequence in the synthesis of a new nortriterpenoid 39.
Scheme 8: Oxidation–Dieckmann cyclization sequence in the synthesis of 18,19-di-nor-cholesterol (40).
Scheme 9: Oxidation–cyclization sequence in the synthesis of 3-ethyl-substituted betulinic acid derivatives 49...
Scheme 10: Benzilic acid-type rearrangement in the synthesis of 4β-acetoxyprobotryane-9β,15α-diol (52).
Scheme 11: Benzilic acid-type rearrangement in the synthesis of (−)-taiwaniaquinone H (11).
Scheme 12: Benzilic acid-type rearrangement in the synthesis of dactylicapnosines A (63) and B (64).
Scheme 13: Aza-benzilic acid-type rearrangement in the synthesis of (+)-stephadiamine (71).
Scheme 14: α-Ketol rearrangement in the synthesis of saffloneoside (73).
Scheme 15: Conversion of (−)-preaustinoid A (80) to (−)-preaustinoid B (81) via α-ketol rearrangement.
Scheme 16: α-Ketol rearrangement in the synthesis of 2,8-oxymethano-bridged diquinane 90.
Scheme 17: Oxidative ring contraction during the synthesis of (+)-cuparene (91) and (+)-tochuinylacetate (92).
Scheme 18: Semipinacol rearrangement in the synthesis of diterpenoids 97–100.
Scheme 19: Co-catalyzed homoallyl-type rearrangement in the syntheses of meroterpenes 106–109.
Scheme 20: Ring contraction reaction promoted by TTN·3H2O and HTIB in the synthesis of indanes.
Scheme 21: Rearrangement involving a hypervalent iodine compound in the synthesis of derivative 120.
Scheme 22: Wolff rearrangement in the synthesis of taiwaniaquinones A (7), F (8), taiwaniaquinols B (10), D (1...
Scheme 23: Wolff rearrangement in the synthesis of cheloviolene C (128), seconorrisolide B (129), and seconorr...
Scheme 24: Wolff rearrangement in the synthesis of (−)-pavidolide B (134).
Scheme 25: Wolff rearrangement in the synthesis of presilphiperfolan-8-ol (141).
Scheme 26: Photochemical rearrangement in the synthesis of cyclopentane derivatives 147a,b.
Scheme 27: Synthesis of cyclopentane derivatives 147a and 151.
Scheme 28: Photochemical rearrangement in the synthesis of cyclopentane derivative 153.
Scheme 29: Photochemical rearrangement in the synthesis of tricyclic ketones 155, 156.
Scheme 30: Photochemical rearrangement in the synthesis of cis/trans salts 160.
Figure 2: Scope of the photoinduced carboborative ring contraction of steroids. Reaction conditions: steroid ...
Scheme 31: Photoinduced carboborative ring contraction in the synthesis of artalbic acid (180).
Scheme 32: Synthetic versatility of the photoinduced carboborative ring contraction.
Scheme 33: Methods of disclosure of epoxide 189.
Scheme 34: Methods of disclosure of epoxide 190.
Scheme 35: Rearrangement of α,β-epoxy ketone 197.
Scheme 36: Acid-induced rearrangement in the synthesis of perhydrindane ketones 202 and 205.
Scheme 37: Rearrangement of epoxyketone 208 in the synthesis of huperzine Q (206).
Scheme 38: Rearrangement of epoxide 212 under the action of Grignard reagent.
Scheme 39: Semipinacol rearrangement of epoxide 220 in the synthesis of (−)-citrinadin A (217) and (+)-citrina...
Scheme 40: Semipinacol rearrangement of epoxide 225 in the synthesis of hamigeran G (223).
Scheme 41: Semipinacol rearrangement of epoxide 231 in the synthesis of (−)-spirochensilide A (228).
Scheme 42: Wagner–Meerwein rearrangement in the synthesis of compound 234 with iridoid topology.
Scheme 43: Wagner–Meerwein rearrangement in the synthesis of compound 238 with iridoid topology.
Scheme 44: Wagner–Meerwein rearrangement in the synthesis of compound 241 with iridoid topology.
Scheme 45: Wagner–Meerwein rearrangement in the synthesis of lupane derivatives 245, 246, 248, and 249.
Scheme 46: Wagner–Meerwein rearrangement in the synthesis of weisaconitine D (252) and cardiopetaline (255).
Scheme 47: Wagner–Meerwein rearrangement in the synthesis of cardiopetaline (255).
The application of desymmetric enantioselective reduction of cyclic 1,3-dicarbonyl compounds in the total synthesis of terpenoid and alkaloid natural products
- Dong-Xing Tan and
- Fu-She Han
Beilstein J. Org. Chem. 2025, 21, 2085–2102, doi:10.3762/bjoc.21.164
- , protection of the resultant primary alcohol, and hydrogenation afforded ketone 65. The LaCl3·LiCl-promoted addition of 65 with Grignard reagent followed by TES protection of the resulting secondary alcohol, regioselective deprotection of the TES group and in situ oxidation provided aldehyde 66. Next, 66
- hydroxyketone 86 in 60% yield with 92% ee and 8.4:1 dr. A secondary hydroxy-directed Grignard reagent addition of 86 followed by selective protection, generated alcohol ester 87. After one recrystallization, the ee value of 87 could be increased to 99%. Subsequently, TMSOTf-promoted transacetalation and in situ
- -catalyzed intermolecular Diels–Alder reaction of 106 with methacrolein 107 afforded the common intermediate 108 in high yield. Sequential Grignard reagent addition and acid-promoted ethoxy elimination provided the separable planar diene 109 (dr = 1:1), which underwent a Mn-catalyzed HAT hydrogenation to
Graphical Abstract
Figure 1: Several representative terpenoid and alkaloid natural products synthesized by applying desymmetric ...
Figure 2: Selected terpenoid and alkaloid natural products synthesized by applying desymmetric enantioselecti...
Scheme 1: The total synthesis of (+)-aplysiasecosterol A (6) by Li [14].
Scheme 2: The total synthesis of (−)-cyrneine A by Han [31].
Scheme 3: The total syntheses of three cyrneine diterpenoids by Han [31,32].
Scheme 4: The total synthesis of (−)-hamigeran B and (−)-4-bromohamigeran B by Han [51].
Scheme 5: The total synthesis of (+)-randainin D by Baudoin [53].
Scheme 6: The total synthesis of (−)-hunterine A and (−)-aspidospermidine by Stoltz [58].
Scheme 7: The total synthesis of (+)-toxicodenane A by Han [65,66].
Scheme 8: The formal total synthesis of (−)-conidiogeone B and total synthesis of (−)-conidiogeone F by Lee a...
Scheme 9: The total syntheses of four conidiogenones natural products by Lee and Han [72].
Scheme 10: The total synthesis of (−)-platensilin by Lou and Xu [82].
Scheme 11: The total synthesis of (−)-platencin and (−)-platensimycin by Lou and Xu [82].
Scheme 12: The total synthesis of (+)-isochamaecydin and (+)-chamaecydin by Han [86].
Synthetic approach to borrelidin fragments: focus on key intermediates
- Yudhi Dwi Kurniawan,
- Zetryana Puteri Tachrim,
- Teni Ernawati,
- Faris Hermawan,
- Ima Nurasiyah and
- Muhammad Alfin Sulmantara
Beilstein J. Org. Chem. 2025, 21, 1135–1160, doi:10.3762/bjoc.21.91
- undesired oxidation to the corresponding phosphane oxide. The work continued with the preparation of the chiral organometallic reagent 124. Starting from known bromide 122, which was readily accessible from Roche ester (R)-121 [52] or 1,3-diol 123 [53][54] through literature procedures, the Grignard reagent
- 124 was obtained by reaction with magnesium in anhydrous diethyl ether. Herber and Breit emphasized that activating the magnesium using a dry stirring method was crucial for smooth magnesiation. The freshly prepared Grignard reagent 124 was added to the allyl electrophile (R)-120 in the presence of
- reaction of a Grignard reagent derived from 133 to the aldehyde counterpart (Scheme 20). Compound 133 was prepared via a cross-metathesis reaction of 2-bromohexa-2,4-dienenitrile 134 and a selection of alkenes. Iqbal noted from the literature that cyano alkenes, such as acrylonitrile, predominantly yielded
Graphical Abstract
Figure 1: Chemical structure of borrelidin (1).
Scheme 1: Synthetic strategy for Morken’s C2–C12 intermediate 20 as reported by Uguen et al. [41].
Scheme 2: Preparation of monoacetates 37 and ent-38 by Uguen et al. [41].
Scheme 3: Preparation of sulfones 27 and ent-27 by Uguen et al. [41].
Scheme 4: Attempts to couple sulfones 27 and ent-27 with epoxides 23a–c reported by Uguen et al. [41].
Scheme 5: Modified synthetic plan for Morken’s C2–C12 intermediate by Uguen [41].
Scheme 6: Revised synthetic strategy for Morken’s C2–C12 intermediate 20 by Uguen [41].
Scheme 7: Iterative synthesis of polydeoxypropionates developed by Zhou et al. [40].
Scheme 8: Application of iterative synthesis of polydeoxypropionate to construct the C3–C11 fragment 60 of bo...
Scheme 9: Retrosynthetic analysis of borrelidin by Yadav et al. [39].
Scheme 10: Two-carbon homologation of precursor 66 in the synthesize C1–C11 fragment 61 of borrelidin [39].
Scheme 11: Synthesis of the C1–C11 fragment 61 of borrelidin from monoalcohol 65 [39].
Scheme 12: Synthetic plan for Theodorakis’ C3–C11 fragment 82 of borrelidin by Laschat et al. [38].
Scheme 13: Synthesis of Theodorakis’ C3–C11 fragment 82 from compound 88 [38].
Scheme 14: Retrosynthesis of 61 and 62b by Minnaard and Madduri [37].
Scheme 15: Synthesis of intermediate 98 by Minnaard and Madduri [37].
Scheme 16: Synthesis of Ōmura’s C1–C11 fragment 61 by Minnaard and Madduri [37].
Scheme 17: Synthesis of fragment 62b of borrelidin as proposed by Minnaard and Madduri [37].
Scheme 18: Iterative directed allylation for the synthesis of deoxypropionates by Herber and Breit [33].
Scheme 19: Iterative copper-mediated directed allyl substitution for the synthesis of Theodorakis’ C3–C11 frag...
Scheme 20: Retrosynthesis of the C3–C17 fragment of borrelidin by Iqbal and co-workers [35].
Scheme 21: Synthesis of key intermediates 137 and 147 for the synthesis of the C3–C17 fragment of borrelidin.
Scheme 22: Synthesis of the C3–C17 fragment 150a,b of borrelidin.
Scheme 23: Synthesis of the C11–C15 fragment 155a of borrelidin.
Scheme 24: Macrocyclization of borrelidin model compounds 155a and 155b using ring-closing metathesis.
A convergent synthetic approach to the tetracyclic core framework of khayanolide-type limonoids
- Zhiyang Zhang,
- Jialei Hu,
- Hanfeng Ding,
- Li Zhang and
- Peirong Rao
Beilstein J. Org. Chem. 2025, 21, 926–934, doi:10.3762/bjoc.21.75
- instability of α-iodoenone 13. Inspired by the influential studies by Knochel [36] and Baran [48], we discovered that Mg/I exchange of 13 could be accomplished with iPrMgCl·LiCl at −78 °C. The resulting Grignard reagent reacted smoothly with aldehyde 14, affording the corresponding adduct 12 in 58% yield (92
Graphical Abstract
Figure 1: Representative limonoid triterpenes.
Scheme 1: Structures and retrosynthetic analysis of krishnolides A (7) and C (8).
Scheme 2: Construction of α-iodoenone 13.
Scheme 3: Construction of aldehyde 14.
Scheme 4: Synthesis of the advanced intermediate 10 (in the X ray structure of 10 solvent molecule is omitted...
Deep-blue emitting 9,10-bis(perfluorobenzyl)anthracene
- Long K. San,
- Sebastian Balser,
- Brian J. Reeves,
- Tyler T. Clikeman,
- Yu-Sheng Chen,
- Steven H. Strauss and
- Olga V. Boltalina
Beilstein J. Org. Chem. 2025, 21, 515–525, doi:10.3762/bjoc.21.39
- crystals, addition of a drop of 1,2-dibromoethane). Only the addition of 1,2-dibromoethane enabled the generation of the Grignard reagent which was observed by bubbles and an instant increase of the reaction mixture’s temperature. CF2C6F5I (97.5 µL, 625 µmol) dissolved in dry THF (20 mL) was added with a
Graphical Abstract
Scheme 1: List of reactions, experimental conditions and yields studied in this work.
Figure 1: Top: 379 MHz 19F NMR spectrum of 9,10-ANTH(BnF)2 in CDCl3. Bottom: absorption (aerobic, solid line)...
Figure 2: Top: X-ray structure of 9,10-ANTH(BnF)2, thermal ellipsoids 50% probability. Bottom: a view down th...
Figure 3: Absorption spectra of ANTH and 9,10-ANTH(BnF)2 in CH2Cl2 recorded over the period of 53 days in air...
Figure 4: Direct analysis in real time (DART) positive ion mass spectrum of the photoirradiated 9,10-ANTH(BnF)...
Figure 5: The % remaining of ANTH and 9,10-ANTH(BnF)2 dissolved in CDCl3 upon irradiation. Resonances δ = 7.4...
Synthesis of the aggregation pheromone of Tribolium castaneum
- Biyu An,
- Xueyang Wang,
- Ao Jiao,
- Qinghua Bian and
- Jiangchun Zhong
Beilstein J. Org. Chem. 2025, 21, 510–514, doi:10.3762/bjoc.21.38
- with Grignard reagent, and oxidation with RuCl3/NaIO4. Keywords: aggregation pheromone; chiral 2-methyloxirane; red flour beetle; total synthesis; Introduction The red flour beetle, Tribolium castaneum Herbst (Coleoptera: Tenebrionidae), is a cosmopolitan, destructive stored product pest [1], which
- olefine (5R,9R)-12, which could be obtained through Li2CuCl4-catalyzed coupling of chiral tosylate (S)-10 with a Grignard reagent derived from (R)-1-bromo-2-methylbutane ((R)-11). The key chiral building block (S)-10 was envisaged to be prepared through a sequence of hydrolyzation, decarboxylation, borane
- prepared the target aggregation pheromone (4R,8R)-1, (4R,8S)-1, (4S,8R)-1, and (4S,8S)-1 (Scheme 4). Li2CuCl4-catalyzed coupling of chiral tosylate (S)-10 with the Grignard reagent derived from (R)-1-bromo-2-methylbutane ((R)-11) and Mg afforded (5R,9R)-5,9-dimethylundec-1-ene ((5R,9R)-12) in 80% yield [35
Graphical Abstract
Figure 1: The aggregation pheromone of Tribolium castaneum.
Scheme 1: Retrosynthetic analysis of the aggregation pheromone (4R,8R)-1.
Scheme 2: Synthesis of chiral tosylate (S)-10.
Scheme 3: Synthesis of chiral tosylate (R)-10.
Scheme 4: Synthesis of the aggregation pheromone of Tribolium castaneum.
Recent advances in organocatalytic atroposelective reactions
- Henrich Szabados and
- Radovan Šebesta
Beilstein J. Org. Chem. 2025, 21, 55–121, doi:10.3762/bjoc.21.6
Graphical Abstract
Scheme 1: Formation of axially chiral styrenes 3 via iminium activation.
Scheme 2: Synthesis of axially chiral 2-arylquinolines 6.
Scheme 3: Atroposelective intramolecular (4 + 2) annulation leading to aryl-substituted indolines.
Scheme 4: Atroposelective formation of biaryl via twofold aldol condensation.
Scheme 5: Strategy towards diastereodivergent formation of axially chiral oligonaphthylenes.
Scheme 6: Atroposelective formation of chiral biaryls based on a Michael/Henry domino reaction.
Scheme 7: Organocatalytic Michael/aldol cascade followed by oxidative aromatization.
Scheme 8: Atroposelective formation of C(sp2)–C(sp3) axially chiral compounds.
Scheme 9: NHC-catalyzed synthesis of axially chiral styrenes 26.
Scheme 10: NHC-catalyzed synthesis of biaxial chiral pyranones.
Scheme 11: Formation of bridged biaryls with eight-membered lactones.
Scheme 12: The NHC-catalyzed (3 + 2) annulation of urazoles 37 and ynals 36.
Scheme 13: NHC-catalyzed synthesis of axially chiral 4‑aryl α‑carbolines 41.
Scheme 14: NHC-catalyzed construction of N–N-axially chiral pyrroles and indoles.
Scheme 15: NHC-catalyzed oxidative Michael–aldol cascade.
Scheme 16: NHC-catalyzed (4 + 2) annulation for the synthesis of benzothiophene-fused biaryls.
Scheme 17: NHC-catalyzed desymmetrization of N-aryl maleimides.
Scheme 18: NHC-catalyzed deracemization of biaryl hydroxy aldehydes 55a–k into axially chiral benzonitriles 56a...
Scheme 19: NHC-catalyzed desymmetrization of 2-aryloxyisophthalaldehydes.
Scheme 20: NHC-catalyzed DKR of 2-arylbenzaldehydes 62.
Scheme 21: Atroposelective biaryl amination.
Scheme 22: CPA-catalyzed atroposelective amination of 2-anilinonaphthalenes.
Scheme 23: Atroposelective DKR of naphthylindoles.
Scheme 24: CPA-catalyzed kinetic resolution of binaphthylamines.
Scheme 25: Atroposelective amination of aromatic amines with diazodicarboxylates.
Scheme 26: Atroposelective Friedländer heteroannulation.
Scheme 27: CPA-catalyzed formation of axially chiral 4-arylquinolines.
Scheme 28: CPA-catalyzed Friedländer reaction of arylketones with cyclohexanones.
Scheme 29: CPA-catalyzed atroposelective Povarov reaction.
Scheme 30: Atroposelective CPA-catalyzed Povarov reaction.
Scheme 31: Paal–Knorr formation of axially chiral N-pyrrolylindoles and N-pyrrolylpyrroles.
Scheme 32: Atroposelective Paal–Knorr reaction leading to N-pyrrolylpyrroles.
Scheme 33: Atroposelective Pictet–Spengler reaction of N-arylindoles with aldehydes.
Scheme 34: Atroposelective Pictet–Spengler reaction leading to tetrahydroisoquinolin-8-ylanilines.
Scheme 35: Atroposelective formation of arylindoles.
Scheme 36: CPA-catalyzed arylation of naphthoquinones with indolizines.
Scheme 37: Atroposelective reaction of o-naphthoquinones.
Scheme 38: CPA-catalyzed formation of axially chiral arylquinones.
Scheme 39: CPA-catalyzed axially chiral N-arylquinones.
Scheme 40: Atroposelective additions of bisindoles to isatin-based 3-indolylmethanols.
Scheme 41: CPA-catalyzed synthesis of axially chiral arylindolylindolinones.
Scheme 42: CPA-catalyzed reaction between bisindoles and ninhydrin-derived 3-indoylmethanols.
Scheme 43: Atroposelective reaction of bisindoles and isatin-derived imines.
Scheme 44: CPA-catalyzed formation of axially chiral bisindoles.
Scheme 45: Atroposelective reaction of 2-naphthols with alkynylhydroxyisoindolinones.
Scheme 46: CPA-catalyzed reaction of indolylnaphthols with propargylic alcohols.
Scheme 47: Atroposelective formation of indolylpyrroloindoles.
Scheme 48: Atroposelective reaction of indolylnaphthalenes with alkynylnaphthols.
Scheme 49: CPA-catalyzed addition of naphthols to alkynyl-2-naphthols and 2-naphthylamines.
Scheme 50: CPA-catalyzed formation of axially chiral aryl-alkene-indoles.
Scheme 51: CPA-catalyzed formation of axially chiral styrenes.
Scheme 52: Atroposelective formation of alkenylindoles.
Scheme 53: Atroposelective formation of axially chiral arylquinolines.
Scheme 54: Atroposelective (3 + 2) cycloaddition of alkynylindoles with azonaphthalenes.
Scheme 55: CPA-catalyzed formation of axially chiral 3-(1H-benzo[d]imidazol-2-yl)quinolines.
Scheme 56: Atroposelective cyclization of 3-(arylethynyl)-1H-indoles.
Scheme 57: Atroposelective three-component heteroannulation.
Scheme 58: CPA-catalyzed formation of arylbenzimidazols.
Scheme 59: CPA-catalyzed reaction of N-naphthylglycine esters with nitrosobenzenes.
Scheme 60: CPA-catalyzed formation of axially chiral N-arylbenzimidazoles.
Scheme 61: CPA-catalyzed formation of axially chiral arylbenzoindoles.
Scheme 62: CPA-catalyzed formation of pyrrolylnaphthalenes.
Scheme 63: CPA-catalyzed addition of naphthols and indoles to nitronaphthalenes.
Scheme 64: Atroposelective reaction of heterobiaryl aldehydes and aminobenzamides.
Scheme 65: Atroposelective cyclization forming N-arylquinolones.
Scheme 66: Atroposelective formation of 9H-carbazol-9-ylnaphthalenes and 1H-indol-1-ylnaphthalene.
Scheme 67: CPA-catalyzed formation of pyrazolylnaphthalenes.
Scheme 68: Atroposelective addition of diazodicarboxamides to azaborinephenols.
Scheme 69: Catalytic formation of axially chiral arylpyrroles.
Scheme 70: Atroposelective coupling of 1-azonaphthalenes with 2-naphthols.
Scheme 71: CPA-catalyzed formation of axially chiral oxindole-based styrenes.
Scheme 72: Atroposelective electrophilic bromination of aminonaphthoquinones.
Scheme 73: Atroposelective bromination of dienes.
Scheme 74: CPA-catalyzed formation of axially chiral 5-arylpyrimidines.
Scheme 75: Atroposelective hydrolysis of biaryloxazepines.
Scheme 76: Atroposelective opening of dinaphthosiloles.
Scheme 77: Atroposelective reduction of naphthylenals.
Scheme 78: Atroposelective allylic substitution with 2-naphthols.
Scheme 79: Atroposelective allylic alkylation with phosphinamides.
Scheme 80: Atroposelective allylic substitution with aminopyrroles.
Scheme 81: Atroposelective allylic substitution with aromatic sulfinamides.
Scheme 82: Atroposelective sulfonylation of naphthylynones.
Scheme 83: Squaramide-catalyzed reaction of alkynyl-2-naphthols with 5H-oxazolones.
Scheme 84: Formation of axially chiral styrenes via sulfonylative opening of cyclopropanols.
Scheme 85: Atroposelective organo-photocatalyzed sulfonylation of alkynyl-2-naphthols.
Scheme 86: Thiourea-catalyzed atroposelective cyclization of alkynylnaphthols.
Scheme 87: Squaramide-catalyzed formation of axially chiral naphthylisothiazoles.
Scheme 88: Atroposelective iodo-cyclization catalyzed by squaramide C69.
Scheme 89: Squaramide-catalyzed formation of axially chiral oligoarenes.
Scheme 90: Atroposelective ring-opening of cyclic N-sulfonylamides.
Scheme 91: Thiourea-catalyzed kinetic resolution of naphthylpyrroles.
Scheme 92: Atroposelective ring-opening of arylindole lactams.
Scheme 93: Atroposelective reaction of 1-naphthyl-2-tetralones and diarylphosphine oxides.
Scheme 94: Atroposelective reaction of iminoquinones with indoles.
Scheme 95: Kinetic resolution of binaphthylalcohols.
Scheme 96: DKR of hydroxynaphthylamides.
Scheme 97: Atroposelective N-alkylation with phase-transfer catalyst C75.
Scheme 98: Atroposelective allylic substitution via kinetic resolution of biarylsulfonamides.
Scheme 99: Atroposelective bromo-functionalization of alkynylarenes.
Scheme 100: Sulfenylation-induced atroposelective cyclization.
Scheme 101: Atroposelective O-sulfonylation of isochromenone-indoles.
Scheme 102: NHC-catalyzed atroposelective N-acylation of anilines.
Scheme 103: Peptide-catalyzed atroposelective ring-opening of lactones.
Scheme 104: Peptide-catalyzed coupling of 2-naphthols with quinones.
Scheme 105: Atroposelective nucleophilic aromatic substitution of fluoroarenes.
Natural resorcylic lactones derived from alternariol
- Joachim Podlech
Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187
Graphical Abstract
Figure 1: Examples of compounds covered in this review categorized in six sub-classes (see text).
Figure 2: Examples of compounds not covered in this review.
Figure 3: Wrongly assigned and thus obsolete structures (details will be discussed in the respective chapters...
Figure 4: Alternariol with the correct IUPAC numbering and an occasionally used numbering based on the biphen...
Figure 5: Alternariol O-methyl ethers.
Figure 6: Alternariol O-glycosides.
Figure 7: Alternariol O-acetates and O-sulfates.
Figure 8: 2-Hydroxy- and 4-hydroxy-substituted alternariol and its O-methyl ethers.
Figure 9: Chloro- and amino-substituted alternariol and its O-methyl ethers.
Figure 10: Presumed alternariol derivatives with non-canonical substitution pattern.
Figure 11: Alternariol derivatives with the 1-methyl group hydroxylated.
Figure 12: Verrulactones: pseudo-dimeric derivatives of altertenuol and related compounds.
Figure 13: Biaryls formed by reductive lactone opening and/or by decarboxylation.
Figure 14: Altenuene and its diastereomers.
Figure 15: 9-O-Demethylated altenuene diastereomers.
Figure 16: Acetylated and methylated altenuene diastereomers.
Figure 17: Altenuene diastereomers modified with lactic acid, pyruvic acid, or acetone.
Figure 18: Neoaltenuene and related compounds.
Figure 19: Dehydroaltenusin and its derivatives.
Scheme 1: Equilibrium of dehydroaltenusin in polar solvents [278].
Figure 20: Further quinoid derivatives.
Figure 21: Dehydroaltenuenes.
Figure 22: Complex aggregates containing dehydroaltenuene substructures and related compounds.
Figure 23: Dihydroaltenuenes.
Figure 24: Altenuic acids and related compounds.
Figure 25: Cyclopentane- and cyclopentene-fused derivatives.
Figure 26: Cyclopentenone-fused derivatives.
Figure 27: Spiro-fused derivatives and a related ring-opened derivative.
Figure 28: Lactones-fused and lactone-substituted derivatives.
Scheme 2: Biosynthesis of alternariol [324].
Scheme 3: Biosynthesis of alternariol and its immediate successors with the genes involved in the respective ...
Scheme 4: Presumed formation of altenuene and its diastereomers and of botrallin.
Scheme 5: Presumed formation of altenuic acids and related compounds.
Scheme 6: A selection of plausible biosynthetic paths to cyclopenta-fused metabolites. (No stereochemistry is...
Scheme 7: Biomimetic synthesis of alternariol (1) by Harris and Hay [66].
Scheme 8: Total synthesis of alternariol (1) by Subba Rao et al. using a Diels–Alder approach [34].
Scheme 9: Total synthesis of alternariol (1) using a Suzuki strategy by Koch and Podlech [62], improved by Kim et...
Scheme 10: Total synthesis of alternariol (1) using an intramolecular biaryl coupling by Abe et al. [63].
Scheme 11: Total synthesis of altenuene (54) and isoaltenuene (55) by Podlech et al. [249].
Scheme 12: Total synthesis of neoaltenuene (69) by Podlech et al. [35].
Scheme 13: Total synthesis of TMC-264 (79) by Tatsuta et al. [185].
Scheme 14: Total synthesis of cephalosol (99) by Koert et al. [304].
Rhodium-catalyzed homo-coupling reaction of aryl Grignard reagents and its application for the synthesis of an integrin inhibitor
- Kazuyuki Sato,
- Satoki Teranishi,
- Atsushi Sakaue,
- Yukiko Karuo,
- Atsushi Tarui,
- Kentaro Kawai,
- Hiroyuki Takeda,
- Tatsuo Kinashi and
- Masaaki Omote
Beilstein J. Org. Chem. 2024, 20, 1341–1347, doi:10.3762/bjoc.20.118
- and Discussion Methodology development In our work towards Rh-catalyzed homo-coupling reactions of benzyl halides, we observed that a similar rhodium–bis(benzyl) complex can also be formed from benzyl halide by using a Grignard reagent instead R2Zn in the presence of RhCl(PPh3)3 to subsequently give
- solvent as the best conditions (Table 2, entry 1). As shown above, the commercially available Grignard reagent 4a gave the corresponding homo-coupled product 3a in a short reaction time at room temperature. Subsequently, for the purpose of expanding the scope of substrates, we examined the in situ
- preparation of the Grignard reagent followed by the homo-coupling reaction. Various conditions were examined and biphenyl (3b) was obtained in 85% yield in a one-pot reaction, when bromobenzene (5b) was treated with 1.5 equiv of Mg (turnings, grade for Grignard reaction) under reflux conditions of THF for 24
Graphical Abstract
Scheme 1: Ullmann and Ullmann-type homo-coupling reactions.
Scheme 2: Rh-catalyzed homo-coupling reactions.
Scheme 3: Rh-catalyzed homo-coupling reaction by using Grignard reagents.
Scheme 4: Rh-catalyzed one-pot Ullmann-type reaction with bromobenzene under optimized reaction conditions.
Figure 1: Scope and limitations for the Rh-catalyzed one-pot Ullmann-type reaction. Conditions: a) The reacti...
Figure 2: Tentative reaction mechanism.
Scheme 5: Synthesis of compound 10n as a candidate for an integrin inhibitor.
(Bio)isosteres of ortho- and meta-substituted benzenes
- H. Erik Diepers and
- Johannes C. L. Walker
Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78
- ). Reaction with a Grignard reagent, hydroboration and oxidation of the organoborane were also possible in high yields (to 188). Similar to ketoprofen bioisostere 189, its inversely substituted isomer iso-189 was also accessible from 185a. Iwabuchi and co-workers also investigated the biological activity of
Graphical Abstract
Figure 1: Scaffolds commonly reported as bioisosteric replacements of para-substituted benzene and examples p...
Figure 2: 1,2-BCPs as isosteres for ortho-and meta-substituted benzenes: comparison of reported exit vector p...
Scheme 1: 1,2-Disubstituted bicyclo[1.1.1]pentanes as isosteres of ortho-substituted benzenes. A: Baran, Coll...
Scheme 2: Synthesis of 1,2-BCPs from BCP 15 by bridge C–H bromination as reported by MacMillan and co-workers ...
Figure 3: Comparative physicochemical data of telmisartan, lomitapide and their BCP isosteres [26,33]. Shake flask d...
Figure 4: 1,2-Disubstituted bicyclo[2.1.1]hexanes as isosteres of ortho-benzenes: Exit vector parameters of t...
Scheme 3: Synthesis of 1,2-disubstituted bicyclo[2.1.1]hexanes via alkene insertion into bicyclo[1.1.0]butane...
Scheme 4: Synthesis of 1,2-disubstituted bicyclo[2.1.1]hexanes via intramolecular crossed [2 + 2] cycloadditi...
Figure 5: Comparison of physicochemical data of fluxapyroxad and boscalid and their 1,2-BCH bioisosteres [36]. Sh...
Figure 6: Antifungal activity of fluxapyroxad, its 1,5-BCH bioisostere (±)-55, boscalid and its bioisostere 1...
Figure 7: 1,5-Disubstituted bicyclo[2.1.1]hexanes as isosteres of ortho-substituted benzenes. Comparison of e...
Scheme 5: Synthesis of 1,5-disubstituted bicyclo[2.1.1]hexanes as isosteres of ortho-benzenes via intramolecu...
Figure 8: Comparison of physicochemical data of fluxapyroxad and boscalid and their 1,5-BCH bioisosteres [45]. Sh...
Figure 9: Antifungal activity of fluxapyroxad, its 1,5-BCH bioisostere (±)-64, boscalid and its bioisostere 1...
Figure 10: 1,5-Disubstituted 3-oxabicylco[2.1.1]hexanes as isosteres for ortho-benzenes: Comparison of exit ve...
Scheme 6: Synthesis of 1,5-disubstituted 3-oxabicyclo[2.1.1]hexanes as isosteres for ortho-benzenes via intra...
Figure 11: Comparison of physicochemical data of fluxapyroxad and boscalid and their 3-oxa-1,5-BCH bioisostere...
Figure 12: Antifungal activity of fluxapyroxad and boscalid and their 3-oxa-1,5-BCH bioisosteres (±)-75 and (±...
Figure 13: 1,2-Disubstituted bicyclo[3.1.1]heptanes as isosteres of ortho-benzenes. Schematic representation o...
Scheme 7: Synthesis of 1,2-disubstituted bicyclo[3.1.1]heptanes as isosteres for ortho-benzenes via alkene in...
Figure 14: 1,2-Disubstituted stellanes as ortho-benzene isosteres: Comparison of selected exit vector paramete...
Scheme 8: Synthesis of 1,2-disubstituted stellanes as isosteres for ortho-benzenes reported by Ryabukhin, Vol...
Figure 15: 1,2-Disubstituted cubanes as ortho-benzene isosteres: Comparison of substituent distances and angle...
Scheme 9: Synthesis of 1,2-disubsituted cubanes as isosteres for ortho-benzenes. A: Synthesis of 1,2-cubane d...
Figure 16: 1,3-Disubstituted bicyclo[2.1.1]hexanes as isosteres of meta-benzenes: comparative exit vector para...
Scheme 10: Synthesis of 1,3-disubstituted bicyclo[2.1.1]hexanes as isosteres for meta-benzenes reported by Wal...
Figure 17: 1,4-Disubstituted bicyclo[2.1.1]hexanes as isosteres of meta-benzenes: comparative exit vector para...
Scheme 11: Synthesis of 1,4-disubstituted bicyclo[2.1.1}hexanes as isosteres for ortho-benzenes via intramolec...
Figure 18: 1,4-Disubstituted-2-oxabicyclo[2.1.1]hexanes as meta-benzene isosteres: comparison of selected exit...
Scheme 12: Synthesis of 1,4-disubstituted 2-oxabicyclo[2.1.1]hexanes as isosteres for meta-benzenes. A: Mykhai...
Figure 19: Comparative physicochemical data for 2- and 3-oxa-1,4-BCHs and para-substituted benzene equivalents...
Figure 20: 1,5-Disubstituted bicyclo[3.1.1]heptanes as isosteres of meta-benzenes: comparison of exit vector p...
Scheme 13: Synthesis of [3.1.1]propellane as a precursor for 1,5-disubsituted bicyclo[3.1.1]heptanes. A: aGass...
Scheme 14: Synthesis of iodine-substituted 1,5-disubstituted bicyclo[3.1.1]heptanes as isosteres for meta-benz...
Scheme 15: Synthesis of nitrogen-, chalcogen- and tin-substituted 1,5-disubstituted bicyclo[3.1.1]heptanes as ...
Figure 21: Comparative physicochemical data of URB597 and 1,5-BCHep isostere 146 [27]. Kinetic aqueous solubility ...
Figure 22: [2]-Ladderanes as isosteres of meta-benzenes: comparison of reported exit vector parameters [63].
Scheme 16: Synthesis of cis-2,6-disubstituted bicyclo[2.2.0]hexanes as isosteres for meta-benzenes. A: Brown a...
Figure 23: Comparative physicochemical data of meta-benzene 158 and [2]-ladderane isostere 159 [63]. Partition coe...
Figure 24: 1,3-Disubstituted cubanes as isosteres of meta-benzenes: comparison of selected exit vector paramet...
Scheme 17: Synthesis of 1,3-disubsituted cubanes as isosteres for meta-benzenes. A: MacMillan and co-workers’ ...
Figure 25: Comparative physicochemical data of lumacaftor and its 1,3-cubane bioisostere 183 [51]. Distribution co...
Figure 26: 1,3-Disubstituted cuneanes as isosteres of meta-benzenes: comparison of selected exit vector parame...
Scheme 18: Synthesis of 1,3-cuneanes as isosteres of meta-benzene. A: Synthesis of 1,3-cuneanes reported by La...
Figure 27: Comparative physicochemical data of sonidegib and its 1,3-cuneane isostere 190 [71]. aSolubility was to...
Figure 28: Exemplary polysubstituted scaffolds related to disubstituted scaffolds suggested as isosteres of or...
(E,Z)-1,1,1,4,4,4-Hexafluorobut-2-enes: hydrofluoroolefins halogenation/dehydrohalogenation cascade to reach new fluorinated allene
- Nataliia V. Kirij,
- Andrey A. Filatov,
- Yurii L. Yagupolskii,
- Sheng Peng and
- Lee Sprague
Beilstein J. Org. Chem. 2024, 20, 452–459, doi:10.3762/bjoc.20.40
- continues to be relevant. One of the methods for the synthesis of allenes was based on the interaction of bromoolefins with organolithium compounds, followed by the elimination of lithium fluoride [29][30][31]. It was logical to assume that in our case a similar reaction of the Grignard reagent 12 with
- aldehyde 9, elimination of MgBrF results in the formation of allene 11. To confirm our hypothesis, we studied the reaction of haloolefins 3 and 7 with iPrMgCl and BuLi. Thus, olefin 3a in Et2O reacted with iPrMgCl solution in THF at −80 °C to form Grignard reagent 12 and by heating the reaction mixture to
Graphical Abstract
Scheme 1: Synthesis of 2,3-dibromo-1,1,1,4,4,4-hexafluorobutane (2).
Scheme 2: Synthesis of (E)-butene 3a.
Scheme 3: Isomerization reaction of (E)-butene 3a to (Z)-butene 3b.
Scheme 4: Synthesis of 2-chloro-3-iodo-1,1,1,4,4,4-hexafluorobutane (5).
Scheme 5: Dehydrohalogenation reaction of 2-chloro-3-iodo-1,1,1,4,4,4-hexafluorobutane (5).
Scheme 6: The reaction of silane 8 with I2/KF.
Scheme 7: The reaction of 3a with iPrMgCl and 4-fluorobenzaldehyde (9).
Scheme 8: The reaction of olefin 3a with iPrMgCl.
Scheme 9: The reaction of (E)-butene 3a with BuLi.
Scheme 10: The reaction of allene 11 with bromine.
Scheme 11: The reaction of allene 11 with ICl.
Scheme 12: Synthesis of 2,3-dibromo-2-chloro-1,1,1,4,4,4-hexafluorobutane (16).
Scheme 13: Synthesis of (Z, E)-2-bromo-3-chloro-1,1,1,4,4,4-hexafluorobut-2-enes (17a,b).
Scheme 14: The reaction of olefins 17a,b with BuLi.
Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review
- Nosheen Beig,
- Varsha Goyal and
- Raj K. Bansal
Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102
- reagents, are commonly used in conjugate addition reactions. In the presence of Grignard reagents, the NHC-precursor salts do not require an addition of base as the Grignard reagent itself performs this role. In this way, Tomioka and co-workers [57] were able to achieve excellent regio- and
Graphical Abstract
Scheme 1: In situ generation of imidazolylidene carbene.
Scheme 2: Hg(II) complex of NHC.
Scheme 3: Isolable and bottlable carbene reported by Arduengo [3].
Scheme 4: First air-stable carbene synthesized by Arduengo in 1992 [5].
Figure 1: General structure of an NHC.
Figure 2: Stabilization of an NHC by donation of the lone pair electrons into the vacant p-orbital (LUMO) at ...
Figure 3: Abnormal NHC reported by Bertrand [8,9].
Figure 4: Cu(d) orbital to σ*C-N(NHC) interactions in NHC–CuX complexes computed at the B3LYP/def2-SVP level ...
Figure 5: Molecular orbital contributions to the NHC–metal bond.
Scheme 5: Synthesis of NHC–Cu(I) complexes by deprotonation of NHC precursors with a base.
Scheme 6: Synthesis of [NHC–CuX] complexes.
Scheme 7: Synthesis of [(ICy)CuX] and [(It-Bu)CuX] complexes.
Scheme 8: Synthesis of iodido-bridged copper–NHC complexes by deprotonation of benzimidazolium salts reported...
Scheme 9: Synthesis of copper complexes by deprotonation of triazolium salts.
Scheme 10: Synthesis of thiazolylidene–Cu(I) complex by deprotonation with KOt-Bu.
Scheme 11: Preparation of NHC–Cu(I) complexes.
Scheme 12: Synthesis of methylmalonic acid-derived anionic [(26a,b)CuCl]Li(THF)2 and zwitterionic (28) heterol...
Scheme 13: Synthesis of diaminocarbene and diamidocarbene (DAC)–Cu(I) complexes.
Scheme 14: Synthesis of the cationic (NHC)2Cu(I) complex 39 from benzimidazolium salts 38 with tetrakis(aceton...
Scheme 15: Synthesis of NHC and ADC (acyclic diamino carbenes) Cu(I) hexamethyldisilazide complexes reported b...
Scheme 16: Synthesis of NHC–copper(I) complexes using an acetylacetonate-functionalized imidazolium zwitterion...
Scheme 17: Synthesis of NHC–Cu(I) complexes through deprotonation of azolium salts with Cu2O.
Scheme 18: Synthesis of NHC–CuBr complex through deprotonation with Cu2O reported by Kolychev [31].
Scheme 19: Synthesis of chiral NHC–CuBr complexes from phenoxyimine-imidazolium salts reported by Douthwaite a...
Scheme 20: Preparation of linear neutral NHC–CuCl complexes through the use of Cu2O. For abbreviations, please...
Scheme 21: Synthesis of abnormal-NHC–copper(I) complexes by Bertrand, Cazin and co-workers [35].
Scheme 22: Microwave-assisted synthesis of thiazolylidene/benzothiazolylidene–CuBr complexes by Bansal and co-...
Scheme 23: Synthesis of NHC–CuX complexes through transmetallation.
Scheme 24: Preparation of six- or seven-membered NHC–Cu(I) complexes through transmetalation from Ag(I) comple...
Scheme 25: Synthesis of 1,2,3-triazolylidene–CuCl complexes through transmetallation of Ag(I) complexes genera...
Scheme 26: Synthesis of NHC–copper complexes having both Cu(I) and Cu(II) units through transmetalation report...
Scheme 27: Synthesis of new [(IPr(CH2)3Si(OiPr)3)CuX] complexes and anchoring on MCM-41.
Scheme 28: Synthesis of bis(trimethylsilyl)phosphide–Cu(I)–NHC complexes through ligand displacement.
Scheme 29: Synthesis of silyl- and stannyl [(NHC)Cu−ER3] complexes.
Scheme 30: Synthesis of amido-, phenolato-, thiophenolato–Cu(NHC) complexes.
Scheme 31: Synthesis of first isolable NHC–Cu–difluoromethyl complexes reported by Sanford et al. [44].
Scheme 32: Synthesis of NHC–Cu(I)–bifluoride complexes reported by Riant, Leyssens and co-workers [45].
Scheme 33: Conjugate addition of Et2Zn to enones catalyzed by an NHC–Cu(I) complex reported by Woodward in 200...
Scheme 34: Hydrosilylation of a carbonyl group.
Scheme 35: NHC–Cu(I)-catalyzed hydrosilylation of ketones reported by Nolan et al. [48,49].
Scheme 36: Application of chiral NHC–CuCl complex 104 for the enantioselective hydrosilylation of ketones.
Scheme 37: Hydrosilylation reactions catalyzed by NHC–Cu(Ot-Bu) complexes.
Scheme 38: NHC–CuCl catalyzed carbonylative silylation of alkyl halides.
Scheme 39: Nucleophilic conjugate addition to an activated C=C bond.
Figure 6: Molecular electrostatic potential maps (MESP) of two NHC–CuX complexes computed at the B3LYP/def2-S...
Scheme 40: Conjugate addition of Grignard reagents to 3-alkyl-substituted cyclohexenones catalyzed by a chiral...
Scheme 41: NHC–copper complex-catalyzed conjugate addition of Grignard reagent to 3-substituted hexenone repor...
Scheme 42: Conjugate addition or organoaluminum reagents to β-substituted cyclic enones.
Scheme 43: Conjugate addition of boronates to acyclic α,β-unsaturated carboxylic esters, ketones, and thioeste...
Scheme 44: NHC–Cu(I)-catalyzed hydroboration of an allene reported by Hoveyda [63].
Scheme 45: Conjugate addition of Et2Zn to cyclohexenone catalyzed by NHC–Cu(I) complex derived from benzimidaz...
Scheme 46: Asymmetric conjugate addition of diethylzinc to 3-nonen-2-one catalyzed by NHC–Cu complexes derived...
Scheme 47: General scheme of a [3 + 2] cycloaddition reaction.
Scheme 48: [3 + 2] Cycloaddition of azides with alkynes catalyzed by NHC–Cu(I) complexes reported by Diez-Gonz...
Scheme 49: Application of NHC–CuCl/N-donor combination to catalyze the [3 + 2] cycloaddition of benzyl azide w...
Scheme 50: [3 + 2] Cycloaddition of azides with acetylenes catalyzed by bis(NHC)–Cu complex 131 and mixed NHC–...
Figure 7: NHC–CuCl complex 133 as catalyst for the [3 + 2] cycloaddition of alkynes with azides at room tempe...
Scheme 51: [3 + 2] Cycloaddition of a bulky azide with an alkynylpyridine using [(NHC)Cu(μ-I)2Cu(NHC)] copper ...
Scheme 52: [3 + 2] Cycloaddition of benzyl azide with phenylacetylene under homogeneous and heterogeneous cata...
Scheme 53: [3 + 2] Cycloaddition of benzyl azide with acetylenes catalyzed by bisthiazolylidene dicopper(I) co...
Figure 8: Copper (I)–NHC linear coordination polymer 137 and its conversion into tetranuclear (138) and dinuc...
Scheme 54: An A3 reaction.
Scheme 55: Synthesis of SiO2-immobilized NHC–Cu(I) catalyst 141 and its application in the A3-coupling reactio...
Scheme 56: Preparation of dual-purpose Ru@SiO2–[(NHC)CuCl] catalyst system 142 developed by Bordet, Leitner an...
Scheme 57: Application of the catalyst system Ru@SiO2–[Cu(NHC)] 142 to the one-pot tandem A3 reaction and hydr...
Scheme 58: A3 reaction of phenylacetylene with secondary amines and aldehydes catalyzed by benzothiazolylidene...
Figure 9: Kohn–Sham HOMOs of phenylacetylene and NHC–Cu(I)–phenylacetylene complex computed at the B3LYP/def2...
Figure 10: Energies of the FMOs of phenylacetylene, iminium ion, and NHC–Cu(I)–phenylacetylene complex compute...
Scheme 59: NHC–Cu(I) catalyzed diboration of ketones 147 by reacting with bis(pinacolato)diboron (148) reporte...
Scheme 60: Protoboration of terminal allenes catalyzed by NHC–Cu(I) complexes reported by Hoveyda and co-worke...
Scheme 61: NHC–CuCl-catalyzed borylation of α-alkoxyallenes to give 2-boryl-1,3-butadienes.
Scheme 62: Regioselective hydroborylation of propargylic alcohols and ethers catalyzed by NHC–CuCl complexes 1...
Scheme 63: NHC–CuOt-Bu-catalyzed semihydrogenation and hydroborylation of alkynes.
Scheme 64: Enantioselective NHC–Cu(I)-catalyzed hydroborations of 1,1-disubstituted aryl olefins reported by H...
Scheme 65: Enantioselective NHC–Cu(I)-catalyzed hydroboration of exocyclic 1,1-disubstituted alkenes reported ...
Scheme 66: Markovnikov-selective NHC–CuOH-catalyzed hydroboration of alkenes and alkynes reported by Jones et ...
Scheme 67: Dehydrogenative borylation and silylation of styrenes catalyzed by NHC–CuOt-Bu complexes developed ...
Scheme 68: N–H/C(sp2)–H carboxylation catalyzed by NHC–CuOH complexes.
Scheme 69: C–H Carboxylation of benzoxazole and benzothiazole derivatives with CO2 using a 1,2,3-triazol-5-yli...
Scheme 70: Use of Cu(I) complex derived from diethylene glycol-functionalized imidazo[1,5,a] pyridin-3-ylidene...
Scheme 71: Allylation and alkenylation of polyfluoroarenes and heteroarenes catalyzed by NHC–Cu(I) complexes r...
Scheme 72: Enantioselective C(sp2)–H allylation of (benz)oxazoles and benzothiazoles with γ,γ-disubstituted pr...
Scheme 73: C(sp2)–H arylation of arenes catalyzed by dual NHC–Cu/NHC–Pd catalytic system.
Scheme 74: C(sp2)–H Amidation of (hetero)arenes with N-chlorocarbamates/N-chloro-N-sodiocarbamates catalyzed b...
Scheme 75: NHC–CuI catalyzed thiolation of benzothiazoles and benzoxazoles.
Synthesis of ether lipids: natural compounds and analogues
- Marco Antônio G. B. Gomes,
- Alicia Bauduin,
- Chloé Le Roux,
- Romain Fouinneteau,
- Wilfried Berthe,
- Mathieu Berchel,
- Hélène Couthon and
- Paul-Alain Jaffrès
Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96
- incorporation of a phenyl group between the glycerol and the lipid chain. The lipid chain was bonded to the aromatic ring in either ortho-, meta-, and para-position [91]. The incorporation of a phenyl moiety starts with the reaction of the Grignard reagent formed from 4-bromoanisole (10.1, the other isomers 2
Graphical Abstract
Figure 1: Chemical structure of some natural ether lipids (ELs).
Figure 2: Synthesis of lyso-PAF and PAF from 1-O-alkylglycerol [64].
Figure 3: Synthesis of lyso-PAF from 1,3-benzylideneglycerol 3.1 [69].
Figure 4: A) Synthesis of the two enantiomers of octadecylglycerol (4.6 and 4.10) from ᴅ-mannitol (4.1); B) s...
Figure 5: Four-step synthesis of PAF 5.6 from (S)-glycidol [73].
Figure 6: Synthesis of 1-O-alkylglycerol A) from solketal, B) from ᴅ- or ʟ-tartaric acid and the intermediate ...
Figure 7: Synthesis of EL building blocks starting from substituted glycidol 7.1a–c [82].
Figure 8: Synthesis of PAF 8.5 by using phosphoramidite 8.2 [86].
Figure 9: Synthesis of oleyl-PAF 9.7 from ʟ-serine [88].
Figure 10: Synthesis of racemic analogues of lyso-PAF 10.8 and PAF 10.9 featuring a phenyl group between the g...
Figure 11: Synthesis of racemic deoxy-lyso-PAF 11.7 and deoxy-PAF 11.8 [91].
Figure 12: Synthesis of racemic thio-PAF 12.8 [93].
Figure 13: Racemic synthesis of 13.6 to illustrate the modification of the glycerol backbone by adding a methy...
Figure 14: Racemic synthesis of 14.5 as an illustration of the introduction of methyl substituents on the glyc...
Figure 15: Synthesis of functionalized sn-2-acyl chains of PC-EL; A) Steglich esterification or acylation reac...
Figure 16: Synthesis of racemic mc-PAF (16.3), a carbamate analogue of PAF [102].
Figure 17: A) Synthesis of (R)-17.2 and (S)-17.6 starting from (S)-solketal (17.1); B) synthesis of N3-PAF (17...
Figure 18: Modification of the phosphocholine polar head to produce PAF analogues [81].
Figure 19: Racemic PAF analogues 19.3 and 19.5 characterized by the absence of the phosphate group [107].
Figure 20: Synthesis of PIP3-PAF (20.7) [108].
Figure 21: Large-scale synthesis of C18-edelfosine (21.8) [116].
Figure 22: Synthesis of C16-edelfosine (22.10) starting from isopropylidene-ʟ-glyceric acid methyl ester (22.1...
Figure 23: Phosphocholine moiety installation by the use of chlorophosphite 23.2 as key reagent [119].
Figure 24: Synthesis of rac-1-alkyl-2-O-methylglycerol (AMG) [120].
Figure 25: Synthesis of stereocontrolled 1-alkyl-2-O-methyl glycerol 25.9 (AMG) from dimethyl ᴅ-tartrate [81].
Figure 26: A) Racemic synthesis of thioether 26.4 [129,130], B) structure of sulfone analogue 26.5 [129].
Figure 27: Stereocontrolled synthesis of C18-edelfosine thioether analogue 27.8 [118].
Figure 28: Synthesis of thioether 28.4 that include a thiophosphate function [134].
Figure 29: Synthesis of ammonium thioether 29.4 and 29.6 [135].
Figure 30: Synthesis of the N-methylamino analogue of edelfosine 30.6 (BN52211) [138].
Figure 31: Synthesis of 1-desoxy analogues of edelfosine; A) with a saturated alkyl chain; B) synthesis of the...
Figure 32: Stereocontrolled synthesis of edelfosine analogue (S)-32.8 featuring a C18:1 lipid chain [142].
Figure 33: Synthesis of edelfosine analogues with modulation of the lipid chain; A) illustration with the synt...
Figure 34: Synthesis of phospholipid featuring a carbamate function to link the lipid chain to the glycerol un...
Figure 35: Synthesis of sesquiterpene conjugates of phospho glycero ether lipids [148].
Figure 36: Racemic synthesis of methyl-substituted glycerol analogues 36.7 and 36.10: A) synthesis of diether ...
Figure 37: Racemic synthesis of ilmofosine (37.6) [155,156].
Figure 38: A) Stereoselective synthesis of 38.5 via a stereoselective hydroboration reaction; B) synthesis of ...
Figure 39: Racemic synthesis of SRI62-834 (39.6) featuring a spiro-tetrahydrofurane heterocycle in position 2 ...
Figure 40: Racemic synthesis of edelfosine analogue 40.5 featuring an imidazole moiety in sn-2 position [160].
Figure 41: Racemic synthesis of fluorine-functionalized EL: A) Synthesis of 41.6 and B) synthesis of 41.8 [161-163].
Figure 42: A) Synthesis of the β-keto-ester 42.6 that also features a decyl linker between the phosphate and t...
Figure 43: Synthesis of phosphonate-based ether lipids; A) edelfosine phosphonate analogue 43.7 and B) thioeth...
Figure 44: Enantioselective synthesis of phosphonates 44.3 and 44.4 [171].
Figure 45: Racemic synthesis of phosphinate-based ether lipid 45.10 [172].
Figure 46: Racemic synthesis of edelfosine arsonium analogue 46.5 [173].
Figure 47: Synthesis of edelfosine dimethylammonium analogue 47.2 [118].
Figure 48: Synthesis of rac-C18-edelfosine methylammonium analogue 48.4 [176].
Figure 49: A) Synthesis of edelfosine N-methylpyrrolidinium analogue 49.2 or N-methylmorpholinium analogue 49.3...
Figure 50: A) Synthesis of edelfosine’s analogue 50.4 with a PE polar group; B) illustration of a pyridinium d...
Figure 51: A) Synthesis of 51.4 featuring a thiazolium cationic moiety; B) synthesis of thiazolium-based EL 51...
Figure 52: Synthesis of cationic ether lipids 52.3, 52.4 and 52.6 [135,183].
Figure 53: Synthesis of cationic carbamate ether lipid 53.5 [184].
Figure 54: Synthesis of cationic sulfonamide 54.5 [185].
Figure 55: Chemical structure of ONO-6240 (55.1) and SRI-63-119 (55.2).
Figure 56: Synthesis of non-ionic ether lipids 56.2–56.9 [188].
Figure 57: Synthesis of ether lipid conjugated to foscarnet 57.6 [189].
Figure 58: A) Synthesis of ether lipid conjugated to arabinofuranosylcytosine; B) synthesis of AZT conjugated ...
Figure 59: Synthesis of quercetin conjugate to edelfosine [191].
Figure 60: Synthesis of 60.8 (Glc-PAF) [194].
Figure 61: A) Synthesis of amino ether lipid 61.7 functionalized with a rhamnose unit and its amide analogue 6...
Figure 62: A) Synthesis of glucose ether lipid 62.4; B) structure of ether lipid 62.5 possessing a maltose uni...
Figure 63: A) Synthesis of glucuronic methyl ester 63.8; B) structure of cellobiose 63.9 and maltose 63.10 ana...
Figure 64: A) Synthesis of maltosyl glycerolipid 64.7; B) structure of lactose analogue 64.8 prepared followin...
Figure 65: A) Asymmetric synthesis of the aglycone moiety starting from allyl 4-methoxyphenyl ether; B) glycos...
Figure 66: A) Synthesis of ohmline possessing a lactose moiety. B) Structure of other glyco glycero lipids pre...
Figure 67: A) Synthesis of lactose-glycerol ether lipid 67.5; B) analogues possessing a maltose (67.6) or meli...
Figure 68: Synthesis of digalactosyl EL 68.6, A) by using trityl, benzyl and acetyl protecting groups, B) by u...
Figure 69: A) Synthesis of α-ohmline; B) structure of disaccharide ether lipids prepared by using similar meth...
Figure 70: Synthesis of lactose ether lipid 70.3 and its analogue 70.6 featuring a carbamate function as linke...
Figure 71: Synthesis of rhamnopyranoside diether 71.4 [196].
Figure 72: Synthesis of 1-O-hexadecyl-2-O-methyl-3-S-(α-ᴅ-1'-thioglucopyranosyl)-sn-glycerol (72.5) [225].
Figure 73: A) Preparation of lipid intermediate 73.4; B) synthesis of 2-desoxy-C-glycoside 73.10 [226].
Figure 74: Synthesis of galactose-pyridinium salt 74.3 [228].
Figure 75: Synthesis of myo-inositol derivative Ino-C2-PAF (75.10) [230].
Figure 76: A) Synthesis of myo-inositol phosphate building block 76.7; B) synthesis of myo-inositolphosphate d...
Figure 77: A) Synthesis of phosphatidyl-3-desoxy-inositol 77.4; B) synthesis of phosphono-3-desoxyinositol 77.9...
Figure 78: A) Structure of diether phosphatidyl-myo-inositol-3,4-diphosphate 78.1; B) synthesis of phosphatidy...
Figure 79: A) Synthesis of diether-phosphatidyl derivative 79.4 featuring a hydroxymethyl group in place of a ...
Figure 80: Synthesis of Glc-amine-PAF [78].
Figure 81: Synthesis of glucosamine ether lipid 81.4 and its analogues functionalized in position 3 of the ami...
Figure 82: Synthesis of fully deprotected aminoglucoside ether lipid 82.5 [246].
Figure 83: Synthesis of C-aminoglycoside 83.12 using Ramberg–Bäcklund rearrangement as a key step [250].
Figure 84: A) List of the most important glyco lipids and amino glyco lipids included in the study of Arthur a...
Figure 85: Synthesis of mannosamine ether lipid 85.6 [254].
Figure 86: A) Synthesis of glucosamine ether lipids with a non-natural ʟ-glucosamine moiety; B) synthesis of e...
Figure 87: A) Structure of the most efficient anticancer agents 87.1–87.4 featuring a diamino glyco ether lipi...
Figure 88: A) Synthesis of diamino glyco ether lipid 87.4; B) synthesis of bis-glycosylated ether lipid 88.10 [256]....
Figure 89: Synthesis of triamino ether lipid 89.4 [260].
Figure 90: Synthesis of chlorambucil conjugate 90.7 [261].
Figure 91: Three main methods for the preparation of glycerol ether lipid 91.3; A) from solketal and via a tri...
Figure 92: Four different methods for the installation of the phosphocholine polar head group; A) method using...
Figure 93: Illustration of two methods for the installation of saccharides or aminosaccharides; A) O-glycosyla...
Pyridine C(sp2)–H bond functionalization under transition-metal and rare earth metal catalysis
- Haritha Sindhe,
- Malladi Mounika Reddy,
- Karthikeyan Rajkumar,
- Akshay Kamble,
- Amardeep Singh,
- Anand Kumar and
- Satyasheel Sharma
Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62
- yields (Scheme 28). In this reaction, Grignard reagent 148 was used as arylation source in excess amount as the reagent underwent homocoupling leading to the formation of biaryl systems under the reaction conditions. 1,2-Dichloro-2-methylpropane (149) was found to be an effective oxidant under the
Graphical Abstract
Figure 1: Representative examples of bioactive natural products and FDA-approved drugs containing a pyridine ...
Scheme 1: Classical and traditional methods for the synthesis of functionalized pyridines.
Scheme 2: Rare earth metal (Ln)-catalyzed pyridine C–H alkylation.
Scheme 3: Pd-catalyzed C–H alkylation of pyridine N-oxide.
Scheme 4: CuI-catalyzed C–H alkylation of N-iminopyridinium ylides with tosylhydrazones (A) and a plausible r...
Scheme 5: Zirconium complex-catalyzed pyridine C–H alkylation.
Scheme 6: Rare earth metal-catalyzed pyridine C–H alkylation with nonpolar unsaturated substrates.
Scheme 7: Heterobimetallic Rh–Al complex-catalyzed ortho-C–H monoalkylation of pyridines.
Scheme 8: Mono(phosphinoamido)-rare earth complex-catalyzed pyridine C–H alkylation.
Scheme 9: Rhodium-catalyzed pyridine C–H alkylation with acrylates and acrylamides.
Scheme 10: Ni–Al bimetallic system-catalyzed pyridine C–H alkylation.
Scheme 11: Iridium-catalyzed pyridine C–H alkylation.
Scheme 12: para-C(sp2)–H Alkylation of pyridines with alkenes.
Scheme 13: Enantioselective pyridine C–H alkylation.
Scheme 14: Pd-catalyzed C2-olefination of pyridines.
Scheme 15: Ru-catalyzed C-6 (C-2)-propenylation of 2-arylated pyridines.
Scheme 16: C–H addition of allenes to pyridines catalyzed by half-sandwich Sc metal complex.
Scheme 17: Pd-catalyzed stereodivergent synthesis of alkenylated pyridines.
Scheme 18: Pd-catalyzed ligand-promoted selective C3-olefination of pyridines.
Scheme 19: Mono-N-protected amino acids in Pd-catalyzed C3-alkenylation of pyridines.
Scheme 20: Amide-directed and rhodium-catalyzed C3-alkenylation of pyridines.
Scheme 21: Bimetallic Ni–Al-catalyzed para-selective alkenylation of pyridine.
Scheme 22: Arylboronic ester-assisted pyridine direct C–H arylation.
Scheme 23: Pd-catalyzed C–H arylation/benzylation with toluene.
Scheme 24: Pd-catalyzed pyridine C–H arylation with potassium aryl- and heteroaryltrifluoroborates.
Scheme 25: Transient activator strategy in pyridine C–H biarylation.
Scheme 26: Ligand-promoted C3-arylation of pyridine.
Scheme 27: Pd-catalyzed arylation of nicotinic and isonicotinic acids.
Scheme 28: Iron-catalyzed and imine-directed C–H arylation of pyridines.
Scheme 29: Pd–(bipy-6-OH) cooperative system-mediated direct pyridine C3-arylation.
Scheme 30: Pd-catalyzed pyridine N-oxide C–H arylation with heteroarylcarboxylic acids.
Scheme 31: Pd-catalyzed C–H cross-coupling of pyridine N-oxides with five-membered heterocycles.
Scheme 32: Cu-catalyzed dehydrative biaryl coupling of azine(pyridine) N-oxides and oxazoles.
Scheme 33: Rh(III)-catalyzed cross dehydrogenative C3-heteroarylation of pyridines.
Scheme 34: Pd-catalyzed C3-selective arylation of pyridines.
Scheme 35: Rhodium-catalyzed oxidative C–H annulation of pyridines to quinolines.
Scheme 36: Rhodium-catalyzed and NHC-directed C–H annulation of pyridine.
Scheme 37: Ni/NHC-catalyzed regio- and enantioselective C–H cyclization of pyridines.
Scheme 38: Rare earth metal-catalyzed intramolecular C–H cyclization of pyridine to azaindolines.
Scheme 39: Rh-catalyzed alkenylation of bipyridine with terminal silylacetylenes.
Scheme 40: Rollover cyclometallation in Rh-catalyzed pyridine C–H functionalization.
Scheme 41: Rollover pathway in Rh-catalyzed C–H functionalization of N,N,N-tridentate chelating compounds.
Scheme 42: Pd-catalyzed rollover pathway in bipyridine-6-carboxamides C–H arylation.
Scheme 43: Rh-catalyzed C3-acylmethylation of bipyridine-6-carboxamides with sulfoxonium ylides.
Scheme 44: Rh-catalyzed C–H functionalization of bipyridines with alkynes.
Scheme 45: Rh-catalyzed C–H acylmethylation and annulation of bipyridine with sulfoxonium ylides.
Scheme 46: Iridium-catalyzed C4-borylation of pyridines.
Scheme 47: C3-Borylation of pyridines.
Scheme 48: Pd-catalyzed regioselective synthesis of silylated dihydropyridines.
Strategies in the synthesis of dibenzo[b,f]heteropines
- David I. H. Maier,
- Barend C. B. Bezuidenhoudt and
- Charlene Marais
Beilstein J. Org. Chem. 2023, 19, 700–718, doi:10.3762/bjoc.19.51
- from 2-bromostyrene (116) via halogen–lithium exchange and quenching with the appropriate heteroatom source (SiR2Cl2, SnMe2Cl2, GeR2Cl2, BBr3). P-Tethered dienes were synthesised via quenching of a 2-vinylphenyl Grignard reagent with phenylphosphonic dichloride (PhPOCl2). O-Tethered dienes were
Graphical Abstract
Figure 1: Dibenzo[b,f]azepine (1a), -oxepine (1b) and -thiepine (1c) as examples of dibenzo[b,f]heteropines (1...
Figure 2: Selected pharmaceuticals with the dibenzo[b,f]azepine skeleton.
Figure 3: Examples of 10,11-dihydrodibenzo[b,f]azepine-based ligands.
Figure 4: The dibenzo[b,f]azepine moiety in dyes with properties suitable for the use in organic light emitti...
Figure 5: Selective bioactive natural products (13–18) containing the dibenzo[b,f]oxepine scaffold and Novart...
Scheme 1: Retrosynthetic approach to 5H-dibenzo[b,f]azepine (1a) from nitrotoluene (22).
Scheme 2: Oxidative coupling of o-nitrotoluene (22) and reduction of 2,2'-dinitrobibenzyl (21) to form 2,2'-d...
Scheme 3: Synthesis of 10,11-dihydro-5H-dibenzo[b,f]azepine (2a) via amine condensation.
Scheme 4: Catalytic reduction of 10,11-dihydro-5H-dibenzo[b,f]azepine (2a).
Scheme 5: The Wagner–Meerwein rearrangement of acridin-9-ylmethanol (23) into 5H-dibenzo[b,f]azepine (1a).
Scheme 6: Oxidative ring expansion of 2-(9-xanthenyl)malonates 24.
Scheme 7: Ring expansion via C–H functionalisation.
Scheme 8: The synthesis of fluorinated 5H-dibenzo[b,f]azepine 38 from isatin (32).
Scheme 9: The synthesis of substituted dibenzo[b,f]azepines 43 from indoles 39.
Scheme 10: Retrosynthetic pathways to dibenzo[b,f]azepines via Buchwald–Hartwig amination.
Scheme 11: Synthesis of dibenzo[b,f]oxepine 54 and -azepine 55 derivatives via (i) Heck reaction and (ii) Buch...
Scheme 12: Double Buchwald–Hartwig amination and thioetherification in the synthesis of tricyclic azepines 60 ...
Scheme 13: Double Buchwald–Hartwig amination towards substituted dibenzoazepines 62.
Scheme 14: Double Buchwald–Hartwig amination towards 10,11-dihydro-5H-dibenzo[b,f]azepine derivatives 71.
Scheme 15: One-pot Suzuki coupling–Buchwald–Hartwig amination.
Scheme 16: One-pot Rh/Pd-catalysed synthesis of dihydropyridobenzazepines.
Scheme 17: A retrosynthetic pathway to dibenzo[b,f]azepines via Mizoroki–Heck reaction.
Scheme 18: One-pot domino Pd-catalyzed Mizoroki–Heck–Buchwald–Hartwig synthesis of dibenzo[b,f]azepines.
Scheme 19: Dibenzo[b,f]thiapine and -oxepine synthesis via SNAr (thio)etherification, Wittig methylenation and...
Scheme 20: A retrosynthetic pathway to dibenzo[b,f]oxepines via Ullmann coupling.
Scheme 21: Ullmann-type coupling in dibenzo[b,f]oxepine synthesis.
Scheme 22: Wittig reaction and Ullmann coupling as key steps in dihydrobenz[b,f]oxepine synthesis.
Scheme 23: Pd-catalysed dibenzo[b,f]azepine synthesis via norbornene azepine intermediate 109.
Scheme 24: A simple representation of olefin metathesis resulting in transalkylidenation.
Scheme 25: Ring-closing metathesis as key step in the synthesis of dibenzo[b,f]heteropines.
Scheme 26: Alkyne–aldehyde metathesis in the synthesis of dibenzo[b,f]heteropines.
Scheme 27: Hydroarylation of 9-(2-alkynylphenyl)-9H-carbazole derivatives.
Scheme 28: Oxidative coupling of bisphonium ylide intermediate to give pacharin (13).
Scheme 29: Preparation of 10,11-dihydrodibenzo[b,f]heteropines via intramolecular Wurtz reaction.
Scheme 30: Phenol deprotonation and intramolecular etherification in the synthesis of bauhinoxepine J.
Figure 6: Functionalisation of dibenzo[b,f]azepine.
Scheme 31: Palladium-catalysed N-arylation of dibenzo[b,f]azepine.
Scheme 32: Cu- and Ni-catalysed N-arylation.
Scheme 33: N-Alkylation of dibenzo[b,f]azepine (1a) and dihydrodibenzo[b,f]azepine (2a).
Scheme 34: Preparation of methoxyiminosilbene.
Scheme 35: Synthesis of oxcarbazepine (153) from methoxy iminostilbene 151.
Scheme 36: Ring functionalisation of dihydrodibenzo[b,f]azepine.
Sequential hydrozirconation/Pd-catalyzed cross coupling of acyl chlorides towards conjugated (2E,4E)-dienones
- Benedikt Kolb,
- Daniela Silva dos Santos,
- Sanja Krause,
- Anna Zens and
- Sabine Laschat
Beilstein J. Org. Chem. 2023, 19, 176–185, doi:10.3762/bjoc.19.17
- deprotonated with LDA at −78 °C in THF and subsequently methylated to give 34 in 99%, followed by treatment with alkynyl Grignard reagent to give the tertiary alcohol 35 in 71% yield. Final elimination with MsCl and NEt3 yielded the desired enyne 25q (49%). When terpene enynes 25p and 25q were submitted to the
Graphical Abstract
Scheme 1: Examples of biologically active compounds with (2Ε,4E)-unsaturated ketone units.
Scheme 2: Selected examples for the synthesis of conjugated dienones from the literature [6-21].
Scheme 3: Previous work of hydrozirconations with Schwartz's reagent and our work [54,55,57,58,61,62].
Scheme 4: Synthesis of substituted enynes 25f–o via Corey–Fuchs reaction and Hunsdiecker reaction.
Scheme 5: Synthesis of non-natural (a) and natural (b) dienone-containing terpenes: synthesis of β-ionone (3)....
Total synthesis of insect sex pheromones: recent improvements based on iron-mediated cross-coupling chemistry
- Eric Gayon,
- Guillaume Lefèvre,
- Olivier Guerret,
- Adrien Tintar and
- Pablo Chourreu
Beilstein J. Org. Chem. 2023, 19, 158–166, doi:10.3762/bjoc.19.15
- -mediated cross-coupling (77% yield for the coupling step, Scheme 4a) [20]. In this cross-coupling, an α,ω-difunctionalized Grignard reagent bearing a magnesium alkoxide moiety at the end of the aliphatic chain is used as a coupling partner. Following in those footsteps, similar syntheses of other insect
- introduction of the C7–C8 linkage by a key iron-mediated cross-coupling sequence between the suitable α,ω-difunctionalized Grignard reagent and 1-bromopenta-1,3-diene as the electrophile (Scheme 6) [32]. A classic drawback of the use of dienyl halides as coupling partners is their intrinsic thermal instability
- ) European grapevine moth, c) horse-chestnut leaf miner) involving a key alkyl–alkenyl iron-mediated cross-coupling between a dienol phosphate and an α,ω-difunctionalized Grignard reagent. Cross-coupling of alkyl Grignard reagents with a) alkenyl or b) aryl halides involving EtOMgCl as additive. Total
Scheme 1: Structure of the (8E,10Z)-tetradecadienal (1, sex pheromone of the horse-chestnut leaf miner) and r...
Scheme 2: a) Alkyl–vinyl seminal cross-coupling reaction by Kochi; b) improved procedure described by Cahiez.
Scheme 3: Iron-catalyzed cross-coupling of n-OctMgCl with a 1-butadienyl phosphate.
Scheme 4: Synthesis of several insect sex pheromones (a) red bollworm moth, b) European grapevine moth, c) ho...
Scheme 5: Cross-coupling of alkyl Grignard reagents with a) alkenyl or b) aryl halides involving EtOMgCl as a...
Scheme 6: Total synthesis of codling moth sex pheromone 4 using an iron-mediated cross-coupling between an α,...
Total synthesis of grayanane natural products
- Nicolas Fay,
- Rémi Blieck,
- Cyrille Kouklovsky and
- Aurélien de la Torre
Beilstein J. Org. Chem. 2022, 18, 1707–1719, doi:10.3762/bjoc.18.181
- synthesis started from 3-hydroxy-2-methoxybenzaldehyde (34), which was converted into Grignard reagent 35 and added onto 3-methylbut-2-enal (Scheme 6). A sequence involving Claisen rearrangement, Roskamp homologation, diazo transfer and intramolecular cyclopropanation led to intermediate 37. The hydroxy
- radical cyclization of an alkynyl ketone as the key step. The synthesis started by a Cu-catalyzed conjugate addition of the vinyl Grignard reagent, followed by TMS α-propargylation under basic conditions, affording the TMS-alkynyl ketone 76 as the major diastereomer (Scheme 11). Originally a Au-catalyzed
Graphical Abstract
Figure 1: General structure of grayanane natural products.
Scheme 1: Grayanane biosynthesis.
Scheme 2: Matsumoto’s relay approach.
Scheme 3: Shirahama’s total synthesis of (–)-grayanotoxin III.
Scheme 4: Newhouse’s syntheses of fragments 25 and 29.
Scheme 5: Newhouse’s total synthesis of principinol D.
Scheme 6: Ding’s total synthesis of rhodomolleins XX and XXII.
Scheme 7: First key step of Luo’s strategy.
Scheme 8: Luo’s total synthesis of grayanotoxin III.
Scheme 9: Synthesis of principinol E and rhodomollein XX.
Scheme 10: William’s synthetic effort towards pierisformaside C.
Scheme 11: Hong’s synthetic effort towards rhodojaponin III.
Scheme 12: Recent strategies for grayanane synthesis.
Modular synthesis of 2-furyl carbinols from 3-benzyldimethylsilylfurfural platforms relying on oxygen-assisted C–Si bond functionalization
- Sebastien Curpanen,
- Per Reichert,
- Gabriele Lupidi,
- Giovanni Poli,
- Julie Oble and
- Alejandro Perez-Luna
Beilstein J. Org. Chem. 2022, 18, 1256–1263, doi:10.3762/bjoc.18.131
- appropriate C3-silylated furfural [15] and dissolved in freshly distilled THF (0.2 M solution). The solution was cooled to 0 °C, and then the Grignard reagent (1.3 equiv in Et2O) was added dropwise (the rate of addition was equal to, or lower than 0.125 mL/min). The mixture was allowed to stir at 0 °C for 1 h
Graphical Abstract
Scheme 1: C3–Si bond functionalization of biomass-derived 3-silylated furfural platforms.
Scheme 2: Preparation of 3-silylated 2-furyl carbinols.
Scheme 3: C–Si bond functionalization of 2,3-disubstituted furyl carbinols by 1,4-silyl migration.
Scheme 4: Attempts of C3–Si bond functionalization promoted by intramolecular activation via alkoxide.
Scheme 5: Alkoxide-promoted cyclic siloxane formation from 2-[(3-benzyldimethylsilyl)furyl] carbinol 4c.
Scheme 6: TBAF-promoted cyclic siloxane formation from 2-[(3-benzyldimethylsilyl)furyl] carbinol 4c.
Scheme 7: Pd-catalyzed arylation of 2-[(3-benzyldimethylsilyl)furyl] carbinol 4c.
Scheme 8: Cu-catalyzed allylation and methylation of 2-[(3-benzyldimethylsilyl)furyl] carbinols. aCuI⋅PPh3 (1...
Recent developments and trends in the iron- and cobalt-catalyzed Sonogashira reactions
- Surendran Amrutha,
- Sankaran Radhika and
- Gopinathan Anilkumar
Beilstein J. Org. Chem. 2022, 18, 262–285, doi:10.3762/bjoc.18.31
- showed better yield of the coupling products. The optimized reaction conditions consisted of 5 mol % of the utilized catalyst with the dropwise addition of Grignard reagent, and 1.2 equivalents of LiBr as an effective additive in THF that resulted in good to excellent yields of the desired products. Bolm
Graphical Abstract
Scheme 1: One pot Sonogashira coupling of aryl iodides with arylynols in the presence of iron(III) chloride h...
Scheme 2: The iron-catalyzed Sonogashira coupling of aryl iodides with terminal acetylenes in water under aer...
Scheme 3: Sonogashira coupling of aryl halides and phenylacetylene in the presence of iron nanoparticles.
Scheme 4: Sonogashira coupling catalyzed by a silica-supported heterogeneous Fe(III) catalyst.
Scheme 5: Suggested catalytic cycle for the Sonogashira coupling using a silica-supported heterogeneous Fe(II...
Scheme 6: Chemoselective iron-catalyzed cross coupling of 4-bromo-1-cyclohexen-1-yltrifluromethane sulfonate ...
Scheme 7: Fe-catalyzed Sonogashira coupling between terminal alkynes and aryl iodides.
Scheme 8: Iron-catalyzed domino Sonogashira coupling and hydroalkoxylation.
Scheme 9: Sonogashira coupling of aryl halides and phenylacetylene in the presence of Fe(III) acetylacetonate...
Scheme 10: Sonogashira coupling of aryl iodides and alkynes with Fe(acac)3/2,2-bipyridine catalyst.
Scheme 11: Sonogashira cross-coupling of terminal alkynes with aryl iodides in the presence of Fe powder/ PPh3...
Scheme 12: α-Fe2O3 nanoparticles-catalyzed coupling of phenylacetylene with aryl iodides.
Scheme 13: Sonogashira cross-coupling reaction between phenylacetylene and 4-substituted iodobenzenes catalyze...
Scheme 14: One-pot synthesis of 2-arylbenzo[b]furans via tandem Sonogashira coupling–cyclization protocol.
Scheme 15: Suggested mechanism of the Fe(III) catalyzed coupling of o-iodophenol with acetylene derivatives.
Scheme 16: Fe3O4@SiO2/Schiff base/Fe(II)-catalyzed Sonogashira–Hagihara coupling reaction.
Scheme 17: Sonogashira coupling using the Fe(II)(bdmd) catalyst in DMF/1,4-dioxane.
Scheme 18: Synthesis of 7-azaindoles using Fe(acac)3 as catalyst.
Scheme 19: Plausible mechanistic pathway for the synthesis of 7-azaindoles.
Scheme 20: Synthesis of Co@imine-POP catalyst.
Scheme 21: Sonogashira coupling of various arylhalides and phenylacetylene in the presence of Co@imine-POP cat...
Scheme 22: Sonogashira coupling of aryl halides and phenylacetylene using Co-DMM@MNPs/chitosan.
Scheme 23: Sonogashira cross-coupling of aryl halides with terminal acetylenes in the presence of Co-NHC@MWCNT...
Scheme 24: Sonogashira cross-coupling of aryl halides with terminal acetylenes in the presence of Co nanoparti...
Scheme 25: Sonogashira coupling reaction of aryl halides with phenylacetylene in the presence of Co nanopartic...
Scheme 26: PdCoNPs-3DG nanocomposite-catalyzed Sonogashira cross coupling of aryl halide and terminal alkynes.
Scheme 27: Sonogashira cross-coupling of aryl halides and phenylacetylene in the presence of graphene-supporte...
Scheme 28: Sonogashira cross-coupling with Pd/Co ANP-PPI-graphene.
Scheme 29: Pd-Co-1(H)-catalyzed Sonogashira coupling reaction.
Scheme 30: The coupling of aryl halides with terminal alkynes using cobalt hollow nanospheres as catalyst.
Scheme 31: A plausible mechanism for the cobalt-catalyzed Sonogashira coupling reaction.
Scheme 32: Sonogashira cross-coupling reaction of arylhalides with phenylacetylene catalyzed by Fe3O4@PEG/Cu-C...
Scheme 33: Plausible mechanism of Sonogashira cross-coupling reaction catalyzed by Fe3O4@PEG/Cu-Co.
Scheme 34: Sonogashira coupling reaction of para-substituted bromobenzenes with phenylacetylene in the presenc...
Scheme 35: Possible mechanism for the visible light-assisted cobalt complex-catalyzed Sonogashira coupling. (R...
Scheme 36: Sonogashira cross-coupling of aryl halides and phenylacetylene using cobalt as additive.
Scheme 37: Plausible mechanism of Sonogashira cross-coupling reaction over [LaPd*]. (Reproduced with permissio...
Iron-catalyzed domino coupling reactions of π-systems
- Austin Pounder and
- William Tam
Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196
- [59]. The authors proposed a plausible catalytic cycle based on a series of mechanistic studies (Scheme 3). First, FeCl2 will react with the aryl Grignard reagent to form an aryliron complex 8 which can undergo a SET with the iodoalkane to yield the radical substrate 9. A 5-exo-dig cyclization will
- produce the pyrrolidinyl methyl radical 10 which may add to the iron center to form the Fe(III) complex 11. Reductive elimination would give rise to the final product, and transmetallation with a Grignard reagent regenerates the active Fe species. Alternatively, release of the aryl radical via ipso-attack
- species is stable enough to be selectively trapped by the less sterically demanding 2° alkyl radical 29. Reductive elimination would form the difunctionalized product and transmetallation with an aryl Grignard reagent regenerates the active Fe species 26, restarting the catalytic cycle. As driving Giese
Graphical Abstract
Figure 1: Price comparison among iron and other transition metals used in catalysis.
Scheme 1: Typical modes of C–C bond formation.
Scheme 2: The components of an iron-catalyzed domino reaction.
Scheme 3: Iron-catalyzed tandem cyclization and cross-coupling reactions of iodoalkanes 1 with aryl Grignard ...
Scheme 4: Three component iron-catalyzed dicarbofunctionalization of vinyl cyclopropanes 14.
Scheme 5: Three-component iron-catalyzed dicarbofunctionalization of alkenes 21.
Scheme 6: Double carbomagnesiation of internal alkynes 31 with alkyl Grignard reagents 32.
Scheme 7: Iron-catalyzed cycloisomerization/cross-coupling of enyne derivatives 35 with alkyl Grignard reagen...
Scheme 8: Iron-catalyzed spirocyclization/cross-coupling cascade.
Scheme 9: Iron-catalyzed alkenylboration of alkenes 50.
Scheme 10: N-Alkyl–N-aryl acrylamide 60 CDC cyclization with C(sp3)–H bonds adjacent to a heteroatom.
Scheme 11: 1,2-Carboacylation of activated alkenes 60 with aldehydes 65 and alcohols 67.
Scheme 12: Iron-catalyzed dicarbonylation of activated alkenes 68 with alcohols 67.
Scheme 13: Iron-catalyzed cyanoalkylation/radical dearomatization of acrylamides 75.
Scheme 14: Synergistic photoredox/iron-catalyzed 1,2-dialkylation of alkenes 82 with common alkanes 83 and 1,3...
Scheme 15: Iron-catalyzed oxidative coupling/cyclization of phenol derivatives 86 and alkenes 87.
Scheme 16: Iron-catalyzed carbosulfonylation of activated alkenes 60.
Scheme 17: Iron-catalyzed oxidative spirocyclization of N-arylpropiolamides 91 with silanes 92 and tert-butyl ...
Scheme 18: Iron-catalyzed free radical cascade difunctionalization of unsaturated benzamides 94 with silanes 92...
Scheme 19: Iron-catalyzed cyclization of olefinic dicarbonyl compounds 97 and 100 with C(sp3)–H bonds.
Scheme 20: Radical difunctionalization of o-vinylanilides 102 with ketones and esters 103.
Scheme 21: Dehydrogenative 1,2-carboamination of alkenes 82 with alkyl nitriles 76 and amines 105.
Scheme 22: Iron-catalyzed intermolecular 1,2-difunctionalization of conjugated alkenes 107 with silanes 92 and...
Scheme 23: Four-component radical difunctionalization of chemically distinct alkenes 114/115 with aldehydes 65...
Scheme 24: Iron-catalyzed carbocarbonylation of activated alkenes 60 with carbazates 117.
Scheme 25: Iron-catalyzed radical 6-endo cyclization of dienes 119 with carbazates 117.
Scheme 26: Iron-catalyzed decarboxylative synthesis of functionalized oxindoles 130 with tert-butyl peresters ...
Scheme 27: Iron‑catalyzed decarboxylative alkylation/cyclization of cinnamamides 131/134.
Scheme 28: Iron-catalyzed carbochloromethylation of activated alkenes 60.
Scheme 29: Iron-catalyzed trifluoromethylation of dienes 142.
Scheme 30: Iron-catalyzed, silver-mediated arylalkylation of conjugated alkenes 115.
Scheme 31: Iron-catalyzed three-component carboazidation of conjugated alkenes 115 with alkanes 101/139b and t...
Scheme 32: Iron-catalyzed carboazidation of alkenes 82 and alkynes 160 with iodoalkanes 20 and trimethylsilyl ...
Scheme 33: Iron-catalyzed asymmetric carboazidation of styrene derivatives 115.
Scheme 34: Iron-catalyzed carboamination of conjugated alkenes 115 with alkyl diacyl peroxides 163 and acetoni...
Scheme 35: Iron-catalyzed carboamination using oxime esters 165 and arenes 166.
Scheme 36: Iron-catalyzed iminyl radical-triggered [5 + 2] and [5 + 1] annulation reactions with oxime esters ...
Scheme 37: Iron-catalyzed decarboxylative alkyl etherification of alkenes 108 with alcohols 67 and aliphatic a...
Scheme 38: Iron-catalyzed inter-/intramolecular alkylative cyclization of carboxylic acid and alcohol-tethered...
Scheme 39: Iron-catalyzed intermolecular trifluoromethyl-acyloxylation of styrene derivatives 115.
Scheme 40: Iron-catalyzed carboiodination of terminal alkenes and alkynes 180.
Scheme 41: Copper/iron-cocatalyzed cascade perfluoroalkylation/cyclization of 1,6-enynes 183/185.
Scheme 42: Iron-catalyzed stereoselective carbosilylation of internal alkynes 187.
Scheme 43: Synergistic photoredox/iron catalyzed difluoroalkylation–thiolation of alkenes 82.
Scheme 44: Iron-catalyzed three-component aminoazidation of alkenes 82.
Scheme 45: Iron-catalyzed intra-/intermolecular aminoazidation of alkenes 194.
Scheme 46: Stereoselective iron-catalyzed oxyazidation of enamides 196 using hypervalent iodine reagents 197.
Scheme 47: Iron-catalyzed aminooxygenation for the synthesis of unprotected amino alcohols 200.
Scheme 48: Iron-catalyzed intramolecular aminofluorination of alkenes 209.
Scheme 49: Iron-catalyzed intramolecular aminochlorination and aminobromination of alkenes 209.
Scheme 50: Iron-catalyzed intermolecular aminofluorination of alkenes 82.
Scheme 51: Iron-catalyzed aminochlorination of alkenes 82.
Scheme 52: Iron-catalyzed phosphinoylazidation of alkenes 108.
Scheme 53: Synergistic photoredox/iron-catalyzed three-component aminoselenation of trisubstituted alkenes 82.
Highly stereocontrolled total synthesis of racemic codonopsinol B through isoxazolidine-4,5-diol vinylation
- Lukáš Ďurina,
- Anna Ďurinová,
- František Trejtnar,
- Ľuboš Janotka,
- Lucia Messingerová,
- Jana Doháňošová,
- Ján Moncol and
- Róbert Fischer
Beilstein J. Org. Chem. 2021, 17, 2781–2786, doi:10.3762/bjoc.17.188
- first prepared synthetically before its isolation from natural crude material, employing a stereoselective addition of an aryl Grignard reagent to a five-membered chiral cyclic nitrone derived from ᴅ-arabinose [2]. Its analytical data were consistent with those for the later isolated natural product
Graphical Abstract
Figure 1: (−)-Codonopsinol B (1) and its N-nor-methyl analogue 2; known inhibition activities against α-gluco...
Scheme 1: Synthetic approach towards (±)-codonopsinol B (1) and its N-nor-methyl analogue 2.
Scheme 2: Synthesis of isoxazolidine-4,5-diol (±)-3. Reagents and conditions: (a) ᴅʟ-proline, CHCl3, rt, 48 h...
Scheme 3: Synthesis of final pyrrolidines (±)-1 and (±)-2. Reagents and conditions: (a) vinyl-MgBr, CeCl3, TH...
Figure 2: Molecular structure of N-Cbz-protected pyrrolidine 12 confirmed by single-crystal X-ray crystallogr...
Strategies for the synthesis of brevipolides
- Yudhi D. Kurniawan and
- A'liyatur Rosyidah
Beilstein J. Org. Chem. 2021, 17, 2399–2416, doi:10.3762/bjoc.17.157
- epoxide using vinyl Grignard reagent followed by esterification with acrylic acid (35) proved to be inefficient due to low reproducibility and poor isolation of product 36. The strategy was altered by changing the terminal epoxide 34 to an allylic alcohol (95%) utilizing dimethyl sulfonium methylide
Graphical Abstract
Figure 1: Structures of brevipolides A–O (1 – 15).
Scheme 1: Retrosynthetic analysis of brevipolide H (8) by Kumaraswamy.
Scheme 2: Attempt to synthesize brevipolide H (8) by Kumaraswamy. (R,R)-Noyori cat. = RuCl[N-(tosyl)-1,2-diph...
Scheme 3: Attempt to synthesize brevipolide H (8) by Kumaraswamy (continued).
Scheme 4: Retrosynthetic analysis of brevipolide H (8) by Hou.
Scheme 5: Synthesis ent-brevipolide H (ent-8) by Hou.
Scheme 6: Retrosynthetic analysis of brevipolide H (8) by Mohapatra.
Scheme 7: Attempt to synthesize brevipolide H (8) by Mohapatra.
Scheme 8: Attempt to synthesize brevipolide H (8) by Mohapatra (continued). (+)-(IPC)2-BCl = (+)-B-chloro-dii...
Scheme 9: Retrosynthetic analysis of brevipolide H (8) by Hou.
Scheme 10: Synthesis of brevipolide H (8) by Hou.
Scheme 11: Retrosynthetic analysis of brevipolide M (13) by Sabitha.
Scheme 12: Synthesis of brevipolide M (13) by Sabitha.
Scheme 13: Retrosynthetic analysis of brevipolides M (13) and N (14) by Sabitha.
Scheme 14: Synthesis of brevipolides M (13) and N (14) by Sabitha.
