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Search for "enantiopure compounds" in Full Text gives 10 result(s) in Beilstein Journal of Organic Chemistry.
Enantioselective total synthesis of putative dihydrorosefuran, a monoterpene with an unique 2,5-dihydrofuran structure
- Irene Torres-García,
- Josefa L. López-Martínez,
- Rocío López-Domene,
- Manuel Muñoz-Dorado,
- Ignacio Rodríguez-García and
- Miriam Álvarez-Corral
Beilstein J. Org. Chem. 2022, 18, 1264–1269, doi:10.3762/bjoc.18.132
- . Analysis of the NMR data of the Mosher's derivatives of 8 suggested (S) configuration for the alcohol (−)-3 [16]. On the other hand, enantiopure acetate (+)-(R)-9 was transformed into diol (+)-(R)-7 by the addition of an excess of MeMgBr. Finally, these enantiopure compounds, α-hydroxyallene (−)-(S)-3 and
Graphical Abstract
Scheme 1: Retrosynthetic scheme of the target molecule 1.
Scheme 2: Synthesis of dihydrofuran-monoterpenoid 1. a) i. O3, −78 °C; ii. PPh3, rt, 76%; b) 1-bromobut-2-yne...
Scheme 3: Racemic resolution of allenol 3 and synthesis of derivatives. a) Lipase AK, vinyl acetate, t-BuOMe,...
Recent advances in the asymmetric phosphoric acid-catalyzed synthesis of axially chiral compounds
- Alemayehu Gashaw Woldegiorgis and
- Xufeng Lin
Beilstein J. Org. Chem. 2021, 17, 2729–2764, doi:10.3762/bjoc.17.185
- of the most important properties of nature, resulting from the nonplanar arrangement of four groups in pairs about a chirality axis. These include atropisomerism [1], chiral allenes, spiranes, spiroindanes, and so on [2][3]. Recently, there emerged an enormous demand for enantiopure compounds, not
Graphical Abstract
Figure 1: Representative examples of axially chiral biaryls, heterobiaryls, spiranes and allenes as ligands a...
Figure 2: Selected examples of axially chiral drugs and bioactive molecules.
Figure 3: Axially chiral functional materials and supramolecules.
Figure 4: Important chiral phosphoric acid scaffolds used in this review.
Scheme 1: Atroposelective aryl–aryl-bond formation by employing a facile [3,3]-sigmatropic rearrangement.
Scheme 2: Atroposelective synthesis of axially chiral biaryl amino alcohols 5.
Scheme 3: The enantioselective reaction of quinone and 2-naphthol derivatives.
Scheme 4: Enantioselective synthesis of multisubstituted biaryls.
Scheme 5: Enantioselective synthesis of axially chiral quinoline-derived biaryl atropisomers mediated by chir...
Scheme 6: Pd-Catalyzed atroposelective C–H olefination of biarylamines.
Scheme 7: Palladium-catalyzed directed atroposelective C–H allylation.
Scheme 8: Enantioselective synthesis of axially chiral (a) aryl indoles and (b) biaryldiols.
Scheme 9: Asymmetric arylation of indoles enabled by azo groups.
Scheme 10: Proposed mechanism for the asymmetric arylation of indoles.
Scheme 11: Enantioselective synthesis of axially chiral N-arylindoles [38].
Scheme 12: Enantioselective [3 + 2] formal cycloaddition and central-to-axial chirality conversion.
Scheme 13: Organocatalytic atroposelective arene functionalization of nitrosonaphthalene with indoles.
Scheme 14: Proposed reaction mechanism for the atroposelective arene functionalization of nitrosonaphthalenes.
Scheme 15: Asymmetric construction of axially chiral naphthylindoles [65].
Scheme 16: Enantioselective synthesis of axially chiral 3,3’-bisindoles [66].
Scheme 17: Atroposelective synthesis of 3,3’-bisiindoles bearing axial and central chirality.
Scheme 18: Enantioselective synthesis of axially chiral 3,3’-bisindoles bearing single axial chirality.
Scheme 19: Enantioselective reaction of azonaphthalenes with various pyrazolones.
Scheme 20: Enantioselective and atroposelective synthesis of axially chiral N-arylcarbazoles [73].
Scheme 21: Atroposelective cyclodehydration reaction.
Scheme 22: Atroposelective construction of axially chiral N-arylbenzimidazoles [78].
Scheme 23: Proposed reaction mechanism for the atroposelective synthesis of axially chiral N-arylbenzimidazole...
Scheme 24: Atroposelective synthesis of axially chiral arylpyrroles [21].
Scheme 25: Synthesis of axially chiral arylquinazolinones and its reaction pathway [35].
Scheme 26: Synthesis of axially chiral aryquinoline by Friedländer heteroannulation reaction and its proposed...
Scheme 27: Povarov cycloaddition–oxidative chirality conversion process.
Scheme 28: Atroposelective synthesis of oxindole-based axially chiral styrenes via kinetic resolution.
Scheme 29: Synthesis of axially chiral alkene-indole frame works [45].
Scheme 30: Proposed reaction mechanism for axially chiral alkene-indoles.
Scheme 31: Atroposelective C–H aminations of N-aryl-2-naphthylamines with azodicarboxylates.
Scheme 32: Synthesis of brominated atropisomeric N-arylquinoids.
Scheme 33: The enantioselective syntheses of axially chiral SPINOL derivatives.
Scheme 34: γ-Addition reaction of various 2,3-disubstituted indoles to β,γ-alkynyl-α-imino esters.
Scheme 35: Regio- and stereoselective γ-addition reactions of isoxazol-5(4H)-ones to β,γ-alkynyl-α-imino ester...
Scheme 36: Synthesis of chiral tetrasubstituted allenes and naphthopyrans.
Scheme 37: Asymmetric remote 1,8-conjugate additions of thiazolones and azlactones to propargyl alcohols.
Scheme 38: Synthesis of chiral allenes from 1-substituted 2-naphthols [107].
Double-headed nucleosides: Synthesis and applications
- Vineet Verma,
- Jyotirmoy Maity,
- Vipin K. Maikhuri,
- Ritika Sharma,
- Himal K. Ganguly and
- Ashok K. Prasad
Beilstein J. Org. Chem. 2021, 17, 1392–1439, doi:10.3762/bjoc.17.98
Graphical Abstract
Figure 1: Double-headed nucleosides. B1 and B2 = nucleobases or heterocyclic/carbocyclic moieties; L = linker....
Scheme 1: Synthesis of 2′-(pyrimidin-1-yl)methyl- or 2′-(purin-9-yl)methyl-substituted double-headed nucleosi...
Scheme 2: Synthesis of double-headed nucleoside 7 having two cytosine moieties.
Scheme 3: Synthesis of double-headed nucleoside 2′-deoxy-2′-C-(2-(thymine-1-yl)ethyl)-uridine (11).
Scheme 4: Double-headed nucleosides 14 and 15 obtained by click reaction.
Scheme 5: Synthesis of the double-headed nucleoside 19.
Scheme 6: Synthesis of the double-headed nucleosides 24 and 25.
Scheme 7: Synthesis of double-headed nucleosides 28 and 29.
Scheme 8: Synthesis of double-headed nucleoside 33.
Scheme 9: Synthesis of double-headed nucleoside 37.
Scheme 10: Synthesis of the double-headed nucleoside 1-(5′-O-(4,4′-dimethoxytrityl)-2′-C-((4-(pyren-1-yl)-1,2,...
Scheme 11: Synthesis of triazole-containing double-headed ribonucleosides 46a–c and 50a–e.
Scheme 12: Synthesis of double-headed nucleosides 54a–g.
Scheme 13: Synthesis of double-headed nucleosides 59 and 60.
Scheme 14: Synthesis of the double-headed nucleosides 63 and 64.
Scheme 15: Synthesis of double-headed nucleosides 66a–c.
Scheme 16: Synthesis of benzoxazole-containing double-headed nucleosides 69 and 71 from 5′-amino-5′-deoxynucle...
Scheme 17: Synthesis of 4′-C-((N6-benzoyladenin-9-yl)methyl)thymidine (75) and 4′-C-((thymin-1-yl)methyl)thymi...
Scheme 18: Synthesis of double-headed nucleosides 5′-(adenine-9-yl)-5′-deoxythymidine (79) and 5′-(adenine-9-y...
Scheme 19: Synthesis of double-headed nucleosides 85–87 via reversed nucleosides methodology.
Scheme 20: Double-headed nucleosides 91 and 92 derived from ω-terminal-acetylenic sugar derivatives 90a,b.
Scheme 21: Synthesis of double-headed nucleosides 96a–g.
Scheme 22: Synthesis of double-headed nucleosides 100 and 103.
Scheme 23: Double-headed nucleosides 104 and 105 with a triazole motif.
Scheme 24: Synthesis of the double-headed nucleosides 107 and 108.
Scheme 25: Synthesis of double-headed nucleoside 110 with additional nucleobase in 5′-(S)-C-position joined th...
Scheme 26: Synthesis of double-headed nucleosides 111–113 with additional nucleobases in the 5′-(S)-C-position...
Scheme 27: Synthesis of double-headed nucleoside 114 by click reaction.
Scheme 28: Synthesis of double-headed nucleosides 118 with an additional nucleobase at the 5′-(S)-C-position.
Scheme 29: Synthesis of bicyclic double-headed nucleoside 122.
Scheme 30: Synthesis of double-headed nucleosides 125a–c derived from 2′-amino-LNA.
Scheme 31: Double-headed nucleoside 127 obtained by click reaction.
Scheme 32: Synthesis of double-headed nucleoside 130.
Scheme 33: Double-headed nucleosides 132a–d and 134a–d synthesized by Sonogashira cross coupling reaction.
Scheme 34: Synthesis of double-headed nucleosides 137 and 138 via Suzuki coupling.
Scheme 35: Synthesis of double-headed nucleosides 140 and 141 via Sonogashira cross coupling reaction.
Scheme 36: Synthesis of double-headed nucleoside 143.
Scheme 37: Synthesis of the double-headed nucleoside 146.
Scheme 38: Synthesis of 5-C-alkynyl-functionalized double-headed nucleosides 151a–d.
Scheme 39: Synthesis of 5-C-triazolyl-functionalized double-headed nucleosides 154a, b.
Scheme 40: Synthesis of double-headed nucleosides 157a–c.
Scheme 41: Synthesis of double-headed nucleoside 159, phosphoramidite 160 and the corresponding nucleotide mon...
Scheme 42: Synthesis of double-headed nucleoside 163, phosphoramidite 164 and the corresponding nucleotide mon...
Scheme 43: Synthesis of double-headed nucleoside 167, phosphoramidite 168, and the corresponding nucleotide mo...
Scheme 44: Synthesis of double-headed nucleoside 171, phosphoramidite 172, and the corresponding nucleotide mo...
Scheme 45: Synthesis of double-headed nucleoside 175, phosphoramidite 176, and the corresponding nucleotide mo...
Scheme 46: Synthesis of double-headed nucleoside 178.
Scheme 47: Synthesis of the double-headed nucleosides 181 and 183.
Scheme 48: Alternative synthesis of the double-headed nucleoside 183.
Scheme 49: Synthesis of double-headed nucleoside 188 through thermal [2 + 3] sydnone–alkyne cycloaddition reac...
Scheme 50: Synthesis of the double-headed nucleosides 190 and 191.
Scheme 51: Synthesis of 1-((5S)-2,3,4-tri-O-acetyl-5-(2,6-dichloropurin-9-yl)-β-ᴅ-xylopyranosyl)uracil (195).
Scheme 52: Synthesis of hexopyranosyl double-headed pyrimidine homonucleosides 200a–c.
Figure 2: 3′-C-Ethynyl-β-ᴅ-allopyranonucleoside derivatives 201a–f.
Scheme 53: Synthesis of 3′-C-(1,4-disubstituted-1,2,3-triazolyl)-double-headed pyranonucleosides 203–207.
Scheme 54: Synthesis of 3′-C-(1,4-disubstituted-1,2,3-triazolyl)-double-headed pyranonucleosides 208 and 209.
Scheme 55: Synthesis of 3′-C-(1,4-disubstituted-1,2,3-triazolyl)-double-headed pyranonucleoside 210.
Scheme 56: Synthesis of double-headed acyclic nucleosides (2S,3R)-1,4-bis(thymine-1-yl)butane-2,3-diol (213a) ...
Scheme 57: Synthesis of double-headed acyclic nucleosides (2R,3S)-1,4-bis(thymine-1-yl)butane-2,3-diol (213c) ...
Scheme 58: Synthesis of double-headed acetylated 1,3,4-oxadiazino[6,5-b]indolium-substituted C-nucleosides 218b...
Scheme 59: Synthesis of double-headed acyclic nucleoside 222.
Scheme 60: Synthesis of functionalized 1,2-bis(1,2,4-triazol-3-yl)ethane-1,2-diols 223a–f.
Scheme 61: Synthesis of acyclic double-headed 1,2,4-triazino[5,6-b]indole C-nucleosides 226–231.
Scheme 62: Synthesis of double-headed 1,3,4-thiadiazoline, 1,3,4-oxadiazoline, and 1,2,4-triazoline acyclo C-n...
Scheme 63: Synthesis of double-headed acyclo C-nucleosides 240–242.
Scheme 64: Synthesis of double-headed acyclo C-nucleoside 246.
Scheme 65: Synthesis of acyclo double-headed nucleoside 250.
Scheme 66: Synthesis of acyclo double-headed nucleoside 253.
Scheme 67: Synthesis of acyclo double-headed nucleosides 259a–d.
Scheme 68: Synthesis of acyclo double-headed nucleoside 261.
Recent applications of chiral calixarenes in asymmetric catalysis
- Mustafa Durmaz,
- Erkan Halay and
- Selahattin Bozkurt
Beilstein J. Org. Chem. 2018, 14, 1389–1412, doi:10.3762/bjoc.14.117
- -opening reaction. Review Phase-transfer catalysis For the past three decades, asymmetric phase-transfer catalysis utilizing chiral quaternary ammonium salts has attracted great interest as a synthetic strategy since it provides quick access to a large number of enantiopure compounds employing only
Graphical Abstract
Figure 1: Inherently chiral calix[4]arene-based phase-transfer catalysts.
Scheme 1: Asymmetric alkylations of 3 catalyzed by (±)-1 and (±)-2 under phase-transfer conditions.
Scheme 2: Synthesis of chiral calix[4]arene-based phase-transfer catalyst 7 and structure of O’Donnell’s N-be...
Scheme 3: Asymmetric alkylation of glycine derivative 3 catalyzed by calixarene-based phase-transfer catalyst ...
Figure 2: Calix[4]arene-amides used as phase-transfer catalysts.
Scheme 4: Phase-transfer alkylation of 3 catalyzed by calixarene-triamide 12.
Scheme 5: Synthesis of inherently chiral calix[4]arenes 20a/20b substituted at the lower rim. Reaction condit...
Scheme 6: Asymmetric Henry reaction between 21 and 22 catalyzed by 20a/20b.
Figure 3: Proposed transition state model of asymmetric Henry reaction.
Scheme 7: Synthesis of enantiomerically pure phosphinoferrocenyl-substituted calixarene ligands 27–29.
Scheme 8: Asymmetric coupling reaction of aryl boronates and aryl halides in the presence of calixarene mono ...
Scheme 9: Asymmetric allylic alkylation in the presence of calix[4]arene ligand (S,S)-29.
Figure 4: Structure of inherently chiral oxazoline calix[4]arenes applied in the palladium-catalyzed Tsuji–Tr...
Scheme 10: Asymmetric Tsuji–Trost reaction in the presence of calix[4]arene ligands 36–39.
Figure 5: BINOL-derived calix[4]arene-diphosphite ligands.
Scheme 11: Asymmetric hydrogenation of 41a and 41b catalyzed by in situ-generated catalysts comprised of [Rh(C...
Figure 6: Inherently chiral calix[4]arene 43 containing a diarylmethanol structure.
Scheme 12: Asymmetric Michael addition reaction of 44 with 45 catalyzed by 43.
Figure 7: Calix[4]arene-based chiral primary amine–thiourea catalysts.
Scheme 13: Asymmetric Michael addition of 48 with 49 catalyzed by 47a and 47b.
Scheme 14: Enantioselective Michael addition of 51 to 52 catalyzed by calix[4]arene thioureas.
Scheme 15: Synthesis of calix[4]arene-based tertiary amine–thioureas 54–56.
Scheme 16: Asymmetric Michael addition of 34 and 57 to nitroalkenes 49 catalyzed by 54b.
Scheme 17: Synthesis of p-tert-butylcalix[4]arene bis-squaramide derivative 64.
Scheme 18: Asymmetric Michael addition catalyzed by 64.
Scheme 19: Synthesis of chiral p-tert-butylphenol analogue 68.
Figure 8: Novel prolinamide organocatalysts based on the calix[4]arene scaffold.
Scheme 20: Asymmetric aldol reactions of 72 with 70 and 71 catalyzed by 69b.
Scheme 21: Synthesis of p-tert-butylcalix[4]arene-based chiral organocatalysts 75 and 78 derived from L-prolin...
Scheme 22: Synthesis of upper rim-functionalized calix[4]arene-based L-proline derivative 83.
Scheme 23: Synthesis and proposed structure of Calix-Pro-MN (86).
Figure 9: Calix[4]arene-based L-proline catalysts containing ester, amide and acid units.
Scheme 24: Synthesis of calix[4]arene-based prolinamide 92.
Scheme 25: Calixarene-based catalysts for the aldol reaction of 21 with 70.
Scheme 26: Asymmetric aldol reactions of 72 with cyclic ketones catalyzed by calix[4]arene-based chiral organo...
Figure 10: A proposed structure for catalyst 92 in H2O.
Scheme 27: Synthetic route for organocatalyst 98.
Scheme 28: Asymmetric aldol reactions catalyzed by 99.
Figure 11: Proposed catalytic environment for catalyst 99 in the presence of water.
Scheme 29: Asymmetric aldol reactions between 94 and 72 catalyzed by 55a.
Scheme 30: Enantioselective Biginelli reactions catalyzed by 69f.
Scheme 31: Synthesis of calix[4]arene–(salen) complexes.
Scheme 32: Enantioselective epoxidation of 108 catalyzed by 107a/107b.
Scheme 33: Synthesis of inherently chiral calix[4]arene catalysts 111 and 112.
Scheme 34: Enantioselective MPV reduction.
Scheme 35: Synthesis of chiral calix[4]arene ligands 116a–c.
Scheme 36: Asymmetric MPV reduction with chiral calix[4]arene ligands.
Scheme 37: Chiral AlIII–calixarene complexes bearing distally positioned chiral substituents.
Scheme 38: Asymmetric MPV reduction in the presence of chiral calix[4]arene diphosphites.
Scheme 39: Synthesis of enantiomerically pure inherently chiral calix[4]arene phosphonic acid.
Scheme 40: Asymmetric aza-Diels–Alder reactions catalyzed by (cR,pR)-121.
Scheme 41: Asymmetric ring opening of epoxides catalyzed by (cR,pR)-121.
Novel amide-functionalized chloramphenicol base bifunctional organocatalysts for enantioselective alcoholysis of meso-cyclic anhydrides
- Lingjun Xu,
- Shuwen Han,
- Linjie Yan,
- Haifeng Wang,
- Haihui Peng and
- Fener Chen
Beilstein J. Org. Chem. 2018, 14, 309–317, doi:10.3762/bjoc.14.19
- great utility of chloramphenicol base scaffold in industrial production of enantiopure compounds is the synthesis of a precursor of biotin (vitamin H) by the chloramphenicol base-promoted asymmetric methanolysis of meso-cyclic anhydrides [41][42][43]. Despite extensive studies on chloramphenicol-base
Graphical Abstract
Figure 1: Chloramphenicol-base-derived bifunctional organocatalysts.
Figure 2: Design of new chloramphenicol base amide organocatalysts.
Scheme 1: Synthesis of bifunctional amide catalysts 7a–q.
Scheme 2: Asymmetric synthesis of (S)-GABOB (13).
Chromium(II)-catalyzed enantioselective arylation of ketones
- Gang Wang,
- Shutao Sun,
- Ying Mao,
- Zhiyu Xie and
- Lei Liu
Beilstein J. Org. Chem. 2016, 12, 2771–2775, doi:10.3762/bjoc.12.275
- ; asymmetric catalysis; chromium; ketone; tertiary alcohol; Introduction Catalytic enantioselective carbon–carbon bond formation reactions have achieved enormous development during the last few decades as a consequence of the growing demand for enantiopure compounds in modern industry, especially the
Graphical Abstract
Scheme 1: Scope of the catalytic enantioselective Cr-mediated arylation of ketones.
Synthesis of 2-oxindoles via 'transition-metal-free' intramolecular dehydrogenative coupling (IDC) of sp2 C–H and sp3 C–H bonds
- Nivesh Kumar,
- Santanu Ghosh,
- Subhajit Bhunia and
- Alakesh Bisai
Beilstein J. Org. Chem. 2016, 12, 1153–1169, doi:10.3762/bjoc.12.111
- -arylamido allyl ester 19c to yield the enantiopure compounds of type 20a and b in good yields [78][79][80][81]. Especially, enantioenriched 20b is the advanced intermediate for the total syntheses of 3a,3a'-bispyrrolo[2,3-b]indole alkaloids, chimonanthine (22a), folicanthine (22b), and their rearranged
Graphical Abstract
Scheme 1: Synthesis of 2-oxindoles via oxidative processes.
Figure 1: Substrates scope of one-pot ‘transition-metal-free’ IDC. The syntheses of compounds 4a–s according ...
Figure 2: Further substrates scope of one-pot ‘transition metal-free’ IDC. Conditions A: KOt-Bu, iodine; cond...
Figure 3: Substrates scope of ‘transition-metal-free’ IDC using KOt-Bu/I2. Reproduced from [46].
Figure 4: C-Alkylation of anilides using KOt-Bu.
Figure 5: Substrates scope of ‘transition-metal-free’ IDC of C-alkylated anilides using DBU/I2.
Scheme 2: Oxidative coupling of C-arylated anilides (±)-11a–d. The synthesis of 12b as per method A has been ...
Scheme 3: Synthesis of spirocyclic product through IDC The synthesis of 14 as per method A has been reproduce...
Scheme 4: Dimerization of β-N-aryl-amidoesters 3a and b. Reproduced from [46].
Scheme 5: Synthesis of dimeric 2-oxindoles utilizing IDC. The syntheses of 19a and b have been reproduced fro...
Scheme 6: Plausible mechanism of ‘transition-metal-free’ IDC The mechanistic consideration in Scheme 6 has been repro...
Scheme 7: Intramolecular-dehydrogenative-coupling (IDC) of 3a and 5a. Reproduced from [46].
Scheme 8: IDC of 3a and 5a using different oxidants. Reproduced from [46].
Scheme 9: Synthesis of 3-substituted-2-oxindoles from benzyl esters.
Scheme 10: 3-Substituted-2-oxindoles from p-methoxybenzyl esters.
Scheme 11: Synthetic elaboration using Tsuji–Trost reactions. Reproduced from [46].
1H-Imidazol-4(5H)-ones and thiazol-4(5H)-ones as emerging pronucleophiles in asymmetric catalysis
- Antonia Mielgo and
- Claudio Palomo
Beilstein J. Org. Chem. 2016, 12, 918–936, doi:10.3762/bjoc.12.90
- Antonia Mielgo Claudio Palomo Departamento de Química Orgánica I, Facultad de Química, Universidad del País Vasco, Apdo. 1072, 20080 San Sebastián, Spain 10.3762/bjoc.12.90 Abstract Asymmetric catalysis represents a very powerful tool for the synthesis of enantiopure compounds. In this context
Graphical Abstract
Figure 1: Some α-substituted heterocycles for asymmetric catalysis, their reactivity patterns against enoliza...
Figure 2: 1H-Imidazol-4(5H)-ones 1 and thiazol-4(5H)-ones 2.
Scheme 1: a) Synthesis of 2-thio-1H-imidazol-4(5H)-ones [55] and b) preparation of the starting thiohydantoins [59].
Scheme 2: Selected examples of the Michael addition of 2-thio-1H-imidazol-4(5H)-ones to nitroalkenes [55]. aReact...
Scheme 3: Michael addition of thiohydantoins to nitrostyrene assisted by Et3N and catalysts C1 and C3. aAbsol...
Scheme 4: Elaboration of the Michael adducts coming from the Michael addition to nitroalkenes [55].
Figure 3: Proposed model for the Michael addition of 1H-imidazol4-(5H)-ones and selected 1H NMR data which su...
Scheme 5: Michael addition 2-thio-1H-imidazol-4(5H)-ones to the α-silyloxyenone 29 [55].
Scheme 6: Elaboration of the Michael adducts coming from the Michael addition to nitroolefins [55].
Scheme 7: Rhodanines in asymmetric catalytic reactions: a) Reaction with rhodanines of type 44 [78-80]; b) reactions...
Scheme 8: Michael addition of thiazol-4(5H)-ones to nitroolefins promoted by the ureidopeptide-like bifunctio...
Figure 4: Ureidopeptide-like Brønsted bases: catalyst design. a) Previous known design. b) Proposed new desig...
Scheme 9: Ureidopeptide-like Brønsted base bifunctional catalyst preparation. NMM = N-methylmorpholine, THF =...
Scheme 10: Selected examples of the Michael addition of thiazolones to different nitroolefins promoted by cata...
Scheme 11: Elaboration of the Michael adducts to α,α-disubstituted α-mercaptocarboxylic acid derivatives [85].
Scheme 12: Effect of the nitrogen atom at the aromatic substituent of the thiazolone on yield and stereoselect...
Scheme 13: Michael addition reaction of thiazol-4(5H)ones 74 to α’-silyloxyenone 29 [73].
Scheme 14: Elaboration of the thiazolone Michael adducts [73].
Scheme 15: Enantioselective γ-addition of oxazol-4(5H)-ones and thiazol-4(5H)-ones to allenoates promoted by C6...
Scheme 16: Enantioselective γ-addition of thiazol-4(5H)-ones and oxazol-4(5H)-ones to alkynoate 83 promoted by ...
Scheme 17: Proposed mechanism for the C6-catalyzed γ-addition of thiazol-4(5H)-one to allenoates. Adapted from ...
Scheme 18: Catalytic enantioselective α-amination of thiazolones promoted by ureidopeptide like catalysts C5 a...
Scheme 19: Iridium-catalized asymmetric allyllation of substituted oxazol-4(5H)-ones and thiazol-4(5H)-ones pr...
Synthesis of 5-oxyquinoline derivatives for reversal of multidrug resistance
- Torsten Dittrich,
- Nils Hanekop,
- Nacera Infed,
- Lutz Schmitt and
- Manfred Braun
Beilstein J. Org. Chem. 2012, 8, 1700–1704, doi:10.3762/bjoc.8.193
- better for Pdr5. Keywords: acetals; enantiopure compounds; heterocycles; inhibitor; multidrug resistance; Introduction The treatment of cancer is often severely hampered by efflux pumps, which are responsible for the extrusion of various chemotherapeutics from the tumor cell, an effect termed
Graphical Abstract
Scheme 1: Lead structure of zosuquidar (1a) and new inhibitors 2–13 (series a); precursors 2–13 (series b); p...
Scheme 2: Synthetic route to compounds 2a–13a. Reagents and conditions: (a) K3PO4, CH2Cl2, reflux, 3 h; then ...
Scheme 3: Preparation of N-Boc-protected 4-aminopiperidines 3c and 4c. Reagents and conditions: (a) NaOt-Bu, ...
A convenient allylsilane- N-acyliminium route toward indolizidine and quinolizidine alkaloids
- Roland Remuson
Beilstein J. Org. Chem. 2007, 3, No. 32, doi:10.1186/1860-5397-3-32
- seven steps and 20% overall yield. [49] II 1.2 Synthesis of (+)-myrtine and (-)-epimyrtine We used a similar strategy to prepare the enantiopure compounds starting from (S)-2-(hydroxypropyl)allyltrimethylsilane 32 (cf. Scheme 9). Compound 32 was obtained in quantitative yield by cerium mediated
Graphical Abstract
Scheme 1: Allylsilane-N-acyliminium cyclisation.
Scheme 2: Enantioselective synthesis of (-)-indolizidine 167B by intramolecular allylsilane-N-acyliminium cyc...
Scheme 3: Synthesis of (±)-indolizidine 167B by intermolecular cyclisation of allylsilane-N-acyliminium cycli...
Scheme 4: Synthesis of 3,5-disubstituted indolizidines from L-pyroglutamic acid.
Scheme 5: Access to indolizidine precursors of dendroprimine starting from chiral 2-aminopropanoate.
Scheme 6: Access to (-)-dendroprimine by reduction with LiAlH4 of indolizidinones 26.
Scheme 7: Access to (-)-dendroprimine by catalytic hydrogenation of indolizidinones 26.
Scheme 8: Synthesis of (±)-myrtine and (±)-epimyrtine.
Scheme 9: Enantioselective synthesis of (+)-myrtine and (-)-epimyrtine.
Scheme 10: Synthesis of (±)-lasubines I and II and (±)-2-epilasubine II.
Scheme 11: Synthesis of (±)-lasubine I and II.
Scheme 12: Enantioselective synthesis of (-)-lasubines I and II and (+)-subcosine.
