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Search for "sterically-hindered" in Full Text gives 285 result(s) in Beilstein Journal of Organic Chemistry. Showing first 200.
Circumventing Mukaiyama oxidation: selective S–O bond formation via sulfenamide–alcohol coupling
- Guoling Huang,
- Huarui Zhu,
- Shuting Zhou,
- Wanlin Zheng,
- Fangpeng Liang,
- Zhibo Zhao,
- Yifei Chen and
- Xunbo Lu
Beilstein J. Org. Chem. 2026, 22, 158–166, doi:10.3762/bjoc.22.9
- good to excellent yields (up to 99%), suggesting broad functional group compatibility. The protocol also demonstrated excellent compatibility with structurally and electronically distinct amide substrates. The sterically hindered 2-naphthylamide-derived sulfenamide afforded the desired product 3h’ in
- efficiently even with secondary hydroxy groups. The method also accommodated sterically hindered and functionalized alcohols. tert-Butylmethanol in which the hydroxy group is attached to a methylene adjacent to a bulky tert-butyl group, gave the desired product 3v’ in 91% yield, while a halogenated alcohol
- with alcohols to access sulfinimidate esters. The method uses inexpensive and readily available reagents and features a broad substrate scope, high chemoselectivity, and excellent tolerance toward sterically hindered and functionalized alcohols. It avoids typical Mukaiyama-type oxidation pathways and
Graphical Abstract
Figure 1: Representative molecules containing a sulfilimine moiety.
Scheme 1: PIDA-mediated approach versus the present NBS-mediated approach to sulfinimidate esters.
Scheme 2: Substrate scope of sulfenamides derived from various thiophenols and thiols. Reaction conditions: s...
Scheme 3: Substrate scope of sulfenamides derived from various amides. Reaction conditions: sulfenamide 1 (0....
Scheme 4: Substrate scope of reactions between sulfenamides 1a and various alcohols. Reaction conditions: asu...
Scheme 5: Scale-up synthesis, late-stage derivatization, and substitution of diastereomeric sulfinimidate est...
Highly electrophilic, gem- and spiro-activated trichloromethylnitrocyclopropanes: synthesis and structure
- Ilia A. Pilipenko,
- Mikhail V. Grigoriev,
- Olga Yu. Ozerova,
- Igor A. Litvinov,
- Darya V. Spiridonova,
- Aleksander V. Vasilyev and
- Sergey V. Makarenko
Beilstein J. Org. Chem. 2026, 22, 123–130, doi:10.3762/bjoc.22.5
- cyclopropane ring is probably a consequence of the formation of a sterically hindered carbanion II in a conformation with an anti-periplanar position of the bulky substituents – bromine and a trichloromethyl group (Scheme 6). Due to the steric reasons, the anion in this conformation is selectively protonated
Graphical Abstract
Figure 1: Two natural trichloromethyl-containing compounds.
Scheme 1: Approaches to the synthesis of vic-trifluoromethylnitrocyclopropanes.
Scheme 2: Synthesis of monocyclic trichloromethylnitrocyclopropanes 2–5.
Scheme 3: Synthesis of spiro-fused trichloromethylnitrocyclopropane 6.
Scheme 4: Synthesis of spiro-fused trichloromethylnitrocyclopropanes 7–9. i: 1.5 AcOK, MeOH, rt, 3 h.
Scheme 5: Main NOE correlations in 9a, 9b.
Scheme 6: Proposed mechanism of the formation of trichloromethylnitrocyclopropanes.
Figure 2: Geometry of 2 in the crystal.
Figure 3: Geometry of 3 in the crystal.
Figure 4: Geometry of 9a in the crystal.
Figure 5: Geometry of 9b in the crystal.
Reactivity umpolung of the cycloheptatriene core in hexa(methoxycarbonyl)cycloheptatriene
- Dmitry N. Platonov,
- Alexander Yu. Belyy,
- Rinat F. Salikov,
- Kirill S. Erokhin and
- Yury V. Tomilov
Beilstein J. Org. Chem. 2026, 22, 64–70, doi:10.3762/bjoc.22.2
- (methoxycarbonyl)cycloheptatriene 3 (pKa(DMSO) = 8.65) [20][21] with potassium tert-butoxide and subjected to reactions with electrophilic reagents. The reactions gave two primary products 4 and 5 (Scheme 1) through an attack to either the most available i-position or the most nucleophilic but sterically hindered
- sterically hindered 2-(methoxycarbonyl)phenyldiazonium ion afforded only one isomer of dihydroindazole 8k which indicates the influence of the steric factor on the azocyclopropane rearrangement. However, the reaction additionally gave the product of an i-substitution with subsequent proton migration to form
- with the formation of 4a,b, as well as the formation of hydrazone product 10k exclusively in the case of the most sterically hindered diazonium electrophile leads to the conclusion that the direct electrophilic attack onto the i-position could take place in all these cases. To clarify this, we analyzed
Graphical Abstract
Figure 1: The expected and the unexpected in selected synthetic strategies.
Figure 2: Distortion in antiaromatic hepta- and hexa(methoxycarbonyl)cycloheptatrienyl anions 1 and 2. HOMO (...
Scheme 1: Reactions of anion 2 generated from cycloheptatriene 3 with halogens and alkyl halides.
Scheme 2: Reactions of anion 2 generated from cycloheptatriene 3 with diazonium salts.
Figure 3: Two conformers of hexa(methoxycarbonyl)cycloheptatrienyl anion 2 and 2'. The energies were obtained...
Scheme 3: Radical mechanism for reactions of anion 2 with halogens, suggested structure of trapped product. T...
Synthesis and applications of alkenyl chlorides (vinyl chlorides): a review
- Daniel S. Müller
Beilstein J. Org. Chem. 2026, 22, 1–63, doi:10.3762/bjoc.22.1
- products 28–35, 38 and 39 [56]). The yields varied considerably depending on the substrate, leading to the following conclusions: (a) unhindered ketones lacking functional groups generally react in high yields; (b) sterically hindered ketones provide products 33, 36, and 39 with low yields; (c) electron
- alkenyl chloride 156 was isolated only in trace amounts, alongside isomerized alkene 157 and dichloride 158. Notably, only the sterically hindered tert-butyl-substituted alkyne afforded the desired product 155 in high yields, whereas hydrochlorination of 4-octyne proved inefficient to deliver compound 159
Graphical Abstract
Figure 1: Representative alkenyl chloride motifs in natural products. References: Pinnaic acid [8], haterumalide ...
Figure 2: Representative alkenyl chloride motifs in pharmaceuticals and pesticides. References: clomifene [25], e...
Figure 3: Graphical overview of previously published reviews addressing the synthesis of alkenyl chlorides.
Figure 4: Classification of synthetic approaches to alkenyl chlorides.
Scheme 1: Early works by Friedel, Henry, and Favorsky.
Scheme 2: Product distribution obtained by H NMR integration of crude compound as observed by Kagan and co-wo...
Scheme 3: Side reactions observed for the reaction of 14 with PCl5.
Scheme 4: Only compounds 15 and 18 were observed in the presence of Hünig’s base.
Scheme 5: Efficient synthesis of dichloride 15 at low temperatures.
Scheme 6: Various syntheses of alkenyl chlorides on larger scale.
Scheme 7: Scope of the reaction of ketones with PCl5 in boiling cyclohexane.
Scheme 8: Side reactions occur when using excess amounts of PCl5.
Scheme 9: Formation of versatile β-chlorovinyl ketones.
Scheme 10: Mixture of PCl5 and PCl3 used for the synthesis of 49.
Scheme 11: Catechol–PCl3 reagents for the synthesis of alkenyl chlorides.
Scheme 12: (PhO)3P–halogen-based reagents for the synthesis of alkenyl halides.
Scheme 13: Preparation of alkenyl chlorides from alkenyl phosphates.
Scheme 14: Preparation of alkenyl chlorides by treatment of ketones with the Vilsmeier reagent.
Scheme 15: Preparation of electron-rich alkenyl chlorides by treatment of ketones with the Vilsmeier reagent.
Scheme 16: Cu-promoted synthesis of alkenyl chlorides from ketones and POCl3.
Figure 5: GC yield of 9 depending on time and reaction temperature.
Figure 6: Broken reaction flask after attempts to clean the polymerized residue.
Figure 7: GC yield of 9 depending on the amount of CuCl and time.
Scheme 17: Treatment of 4-chromanones with PCl3.
Scheme 18: Synthesis of alkenyl chlorides from the reaction of ketones with acyl chlorides.
Scheme 19: ZnCl2-promoted alkenyl chloride synthesis.
Scheme 20: Regeneration of acid chlorides by triphosgene.
Scheme 21: Alkenyl chlorides from ketones and triphosgene.
Scheme 22: Various substitution reactions.
Scheme 23: Vinylic Finkelstein reactions reported by Evano and co-workers.
Scheme 24: Challenge of selective monohydrochlorination of alkynes.
Scheme 25: Sterically encumbered internal alkynes furnish the hydrochlorination products in high yield.
Scheme 26: Recent work by Kropp with HCl absorbed on alumina.
Scheme 27: High selectivities for monhydrochlorination with nitromethane/acetic acid as solvent.
Figure 8: Functionalized alkynes which typically afford the monhydrochlorinated products.
Scheme 28: Related chorosulfonylation and chloroamination reactions.
Scheme 29: Reaction of organometallic reagents with chlorine electrophiles.
Scheme 30: Elimination reactions of dichlorides to furnish alkenyl chlorides.
Scheme 31: Elimination reactions of allyl chloride 182 to furnish alkenyl chloride 183.
Scheme 32: Detailed studies by Schlosser on the elimination of dichloro compounds.
Scheme 33: Stereoselective variation caused by change of solvent.
Scheme 34: Elimination of gem-dichloride 189 to afford alkene 190.
Scheme 35: Oxidation of enones to dichlorides and in situ elimination thereof.
Scheme 36: Oxidation of allylic alcohols to dichlorides and in situ elimination thereof.
Scheme 37: Chlorination of styrenes with SOCl2 and elimination thereof.
Scheme 38: Chlorination of styrenes with SOCl2 and elimination thereof.
Scheme 39: Fluorine–chlorine exchange followed by elimination.
Scheme 40: Intercepting cations with alkynes and trapping of the alkenyl cation intermediate with chloride.
Scheme 41: Investigations by Mayr and co-workers.
Scheme 42: In situ activation of benzyl alcohol 230 with BCl3.
Scheme 43: In situ activation of benzylic alcohols with TiCl4.
Scheme 44: In situ activation of benzylic alcohols with FeCl3.
Scheme 45: In situ activation of benzylic alcohols with FeCl3.
Scheme 46: In situ activation of aliphatic chlorides and alcohols with ZnCl2, InCl3, and FeCl3.
Scheme 47: In situ generation of benzylic cations and trapping thereof with alkynes.
Scheme 48: Intramolecular trapping reactions affording alkenyl halides.
Scheme 49: Intramolecular trapping reactions affording alkenyl chlorides.
Scheme 50: Intramolecular trapping reactions of oxonium and iminium ions affording alkenyl chlorides.
Scheme 51: Palladium and nickel-catalyzed coupling reactions to afford alkenyl chlorides.
Scheme 52: Rhodium-catalyzed couplings of 1,2-trans-dichloroethene with arylboronic esters.
Scheme 53: First report on monoselective coupling reactions for 1,1-dichloroalkenes.
Scheme 54: Negishi’s and Barluenga’s contributions.
Scheme 55: First mechanistic investigation by Johnson and co-workers.
Scheme 56: First successful cross-metathesis with choroalkene 260.
Scheme 57: Subsequent studies by Johnson.
Scheme 58: Hoveyda and Schrock’s work on stereoretentive cross-metathesis with molybdenum-based catalysts.
Scheme 59: Related work with (Z)-dichloroethene.
Scheme 60: Further ligand refinement and traceless protection of functional groups with HBpin.
Scheme 61: Alkenyl chloride synthesis by Wittig reaction.
Scheme 62: Alkenyl chloride synthesis by Julia olefination.
Scheme 63: Alkenyl chloride synthesis by reaction of ketones with Mg/TiCl4 mixture.
Scheme 64: Frequently used allylic substitution reactions which lead to alkenyl chlorides.
Scheme 65: Enantioselective allylic substitutions.
Scheme 66: Synthesis of alkenyl chlorides bearing an electron-withdrawing group.
Scheme 67: Synthesis of α-nitroalkenyl chlorides from aldehydes.
Scheme 68: Synthesis of alkenyl chlorides via elimination of an in situ generated geminal dihalide.
Scheme 69: Carbenoid approach reported by Pace.
Scheme 70: Carbenoid approach reported by Pace.
Scheme 71: Ring opening of cyclopropenes in the presence of MgCl2.
Scheme 72: Electrophilic chlorination of alkenyl MIDA boronates to Z- or E-alkenyl chlorides.
Scheme 73: Hydroalumination and hydroboration of alkynyl chlorides.
Scheme 74: Carbolithiation of chloroalkynes.
Scheme 75: Chlorination of enamine 420.
Scheme 76: Alkyne synthesis by elimination of alkenyl chlorides.
Scheme 77: Reductive lithiation of akenyl chlorides.
Scheme 78: Reactions of alkenyl chlorides with organolithium reagents.
Scheme 79: Reactions of alkenyl chlorides with organolithium reagents.
Scheme 80: Addition–elimination reaction of alkenyl chloride 9 with organolithium reagents.
Scheme 81: C–H insertions of lithiumcarbenoids.
Scheme 82: Pd-catalyzed coupling reactions with alkenyl chlorides as coupling partner.
Scheme 83: Ni-catalyzed coupling of alkenylcopper reagent with alkenyl chloride 183.
Scheme 84: Ni-catalyzed coupling of heterocycle 472 with alkenyl chloride 473.
Scheme 85: Synthesis of α-chloroketones by oxidation of alkenyl chlorides.
Scheme 86: Tetrahalogenoferrate(III)-promoted oxidation of alkenyl chlorides.
Scheme 87: Chlorine–deuterium exchange promoted by a palladium catalyst.
Scheme 88: Reaction of alkenyl chlorides with thiols in the presence of AIBN (azobisisobutyronitrile).
Scheme 89: Chloroalkene annulation.
Tandem hydrothiocyanation/cyclization of CF3-iminopropargyl alcohols with NaSCN in the presence of AcOH
- Ruslan S. Shulgin,
- Ol’ga G. Volostnykh,
- Anton V. Stepanov,
- Igor’ A. Ushakov,
- Alexander V. Vashchenko and
- Olesya A. Shemyakina
Beilstein J. Org. Chem. 2025, 21, 2694–2702, doi:10.3762/bjoc.21.207
- , providing products 2b,c and 3b,c with similar yields (Table 2, entries 1 and 2). The slightly decreased yield observed for product 3c obtained from iminopropargyl alcohol having a cyclohexyl substituent, is probably due to the steric effect (Table 2, entry 2). The more sterically hindered CF3-iminopropargyl
Graphical Abstract
Scheme 1: Examples of hydrothiocyanation/cyclization of alkynes.
Figure 1: 1H and 19F NMR monitoring of 1a/NaSCN/AcOH (a, b) and 1g/NaSCN/AcOH (c, d) reaction mixtures in MeC...
Scheme 2: Plausible reaction mechanism.
Scheme 3: Oxidation of isothiazolium thiocyanate 2a.
Efficient solid-phase synthesis and structural characterization of segetalins A–H, J and K
- Liangyu Liu,
- Wanqiu Lu,
- Quanping Guo and
- Zhaoqing Xu
Beilstein J. Org. Chem. 2025, 21, 2612–2617, doi:10.3762/bjoc.21.202
- from the high cost of the specialized resin and large solvent volumes required for dilution, coupled with DPPA's poor efficiency in forming sterically hindered peptide bonds involving residues like Val or Ile. Dahiya and Kaur synthesized segetalin C (3) via a solution-phase fragment coupling strategy
Graphical Abstract
Scheme 1: Preparation of segetalins A–H, J and K.
Figure 1: Cyclization reactions to segetalins A–H, J and K.
Figure 2: The CD spectra of segetalins A–H, J and K.
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
- the simultaneous construction of four quaternary carbon centers (C1, C4, C5, and C12) and the core AB bicyclic skeleton, markedly improving synthetic efficiency. Subsequent oxidative desymmetrization of the C14–C15 olefin in (±)-33 established the sterically hindered C11 quaternary carbon center. An α
- , (+)-ryanodol (4), indicates that the pyrrole-2-carboxylate unit at the C3 position is critical for receptor binding, as established by structure–activity relationship (SAR) studies [28]. However, the direct and selective modification of the highly sterically hindered C3 hydroxy group within this
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).
Synthetic study toward vibralactone
- Liang Shi,
- Jiayi Song,
- Yiqing Li,
- Jia-Chen Li,
- Shuqi Li,
- Li Ren,
- Zhi-Yun Liu and
- Hong-Dong Hao
Beilstein J. Org. Chem. 2025, 21, 2376–2382, doi:10.3762/bjoc.21.182
- not proceed to form the all-carbon quaternary center and only decomposition of 21 was observed. The failure is likely due to the sterically hindered environment of the substituted β-lactone ring which precludes the C–H insertion or deprotonation of the β-lactone and interrupted the generation of the
Graphical Abstract
Figure 1: Selected representative natural products and derivatives with β-lactone moiety.
Scheme 1: Previous syntheses of vibralactone (6).
Scheme 2: Retrosynthetic analysis of vibralactone (6).
Scheme 3: Synthetic study toward vibralactone (6) in the present of β-lactone.
Scheme 4: C–H insertion utilizing linear precursor 19.
Scheme 5: Construction the bicyclic skeleton of vibralactone (6) through C–H insertion.
Recent advances in Norrish–Yang cyclization and dicarbonyl photoredox reactions for natural product synthesis
- Peng-Xi Luo,
- Jin-Xuan Yang,
- Shao-Min Fu and
- Bo Liu
Beilstein J. Org. Chem. 2025, 21, 2315–2333, doi:10.3762/bjoc.21.177
- natural product synthesis. This review summarizes the latest advancements in these reactions for constructing terpenoids, alkaloids, and antibiotics. Through Norrish–Yang cyclization, dicarbonyls (e.g., 1,2-diketones and α-keto amides) can efficiently construct sterically hindered ring structures, which
- , enabling the construction of diverse architectures including sterically hindered cyclobutanes, spiroketals, and fused polycycles. However, the potential of dicarbonyls in photoreactions warrants further exploration. Future research could investigate a broader range of dicarbonyl substrates to uncover new
Graphical Abstract
Scheme 1: a) The mechanism of Norrish type II reaction and Norrish–Yang cyclization; b) The mechanism of the ...
Scheme 2: Total synthesis of (+)-cyclobutastellettolide B.
Scheme 3: Norrish–Yang cyclization and 1,2-methyl migration.
Scheme 4: Synthetic study toward phainanoids.
Scheme 5: a) Mitsunobu reaction of the C9 ketal; b) Norrish–Yang cyclization of the saturated C5–C6; c) calcu...
Scheme 6: Total synthesis of avarane-type meroterpenoids.
Scheme 7: Total synthesis of gracilisoid A.
Scheme 8: Divergent total synthesis of gracilisoids B–I.
Scheme 9: Mechanism of the late-stage biomimetic photooxidation.
Scheme 10: Asymmetric total synthesis of lycoplatyrine A.
Scheme 11: Photoreaction of pyrrolidine-derived phenyl keto amide.
Scheme 12: Photoredox reactions of naphthoquinones.
Scheme 13: Synthetic study toward γ-rubromycin.
Scheme 14: Substituent-dependent conformational preferences.
Scheme 15: Total synthesis of preussomerins EG1, EG2, and EG3.
Pd-catalyzed dehydrogenative arylation of arylhydrazines to access non-symmetric azobenzenes, including tetra-ortho derivatives
- Loris Geminiani,
- Kathrin Junge,
- Matthias Beller and
- Jean-François Soulé
Beilstein J. Org. Chem. 2025, 21, 2234–2242, doi:10.3762/bjoc.21.170
- efficiency, as the reaction proceeds smoothly even when both coupling partners possess sterically hindered substituents at the 2,6-positions. For example, the coupling of 2,6-difluorophenylhydrazine with 1-bromo-2,6-dimethoxybenzene yielded tetra-ortho-substituted azobenzene 5a in a notable yield of 63
Graphical Abstract
Figure 1: General overview of azobenzene chemistry. a) Selected examples and photoisomerization of azobenzene...
Scheme 1: Scope of aryl bromides in palladium-catalyzed dehydrogenative C–N coupling with phenylhydrazine (1a...
Scheme 2: Scope of arylhydrazines in palladium-catalyzed dehydrogenative C–N coupling with 2-bromotoluene (2a...
Scheme 3: Application to the synthesis of tetra-, tri or di-ortho-substituted azobenzenes via palladium-catal...
Figure 2: a) Proposed catalytic cycle for the one-pot palladium-catalyzed dehydrogenative C–N coupling for th...
C2 to C6 biobased carbonyl platforms for fine chemistry
- Jingjing Jiang,
- Muhammad Noman Haider Tariq,
- Florence Popowycz,
- Yanlong Gu and
- Yves Queneau
Beilstein J. Org. Chem. 2025, 21, 2103–2172, doi:10.3762/bjoc.21.165
Graphical Abstract
Figure 1: C2–C6 biobased carbonyl building blocks.
Scheme 1: Proposed (2 + 2) route to glycolaldehyde and glycolic acid from erythritol by Cu/AC catalyst (AC = ...
Scheme 2: Reductive amination of GCA.
Scheme 3: N-Formylation of secondary amines by reaction with GCA.
Scheme 4: Synthesis and conversion of hydroxy acetals to cyclic acetals.
Scheme 5: Synthesis of 3-(indol-3-yl)-2,3-dihydrofurans via three-component reaction of glycolaldehyde, indol...
Scheme 6: BiCl3-catalyzed synthesis of benzo[a]carbazoles from 2-arylindoles and α-bromoacetaldehyde ethylene...
Scheme 7: Cu/NCNSs-based conversion of glycerol to glycolic acid and other short biobased acids.
Scheme 8: E. coli-based biotransformation of C1 source molecules (CH4, CO2 and CO) towards C2 glycolic acid.
Scheme 9: N-Formylation of amines with C2 (a) or C3 (b) biomass-based feedstocks.
Scheme 10: Methods for the formation of propanoic acid (PA) from lactic acid (LA).
Scheme 11: Co-polymerization of biobased lactic acid and glycolic acid via a bicatalytic process.
Scheme 12: Oxidation of α-hydroxy acids by tetrachloroaurate(III) in acetic acid–sodium acetate buffer medium.
Figure 2: Selective catalytic pathways for the conversion of lactic acid (LA).
Scheme 13: Synthesis of 1,3-PDO via cross-aldol reaction between formaldehyde and acetaldehyde to 3-hydroxypro...
Scheme 14: Hydrothermal conversion of 1,3-dihydroxy-2-propane and 2,3-dihydroxypropanal to methylglyoxal.
Scheme 15: FLS-catalyzed formose reaction to synthesize GA and DHA.
Scheme 16: GCA and DHA oxidation products of glycerol and isomerization of GCA to DHA under flow conditions us...
Scheme 17: Acid-catalyzed reactions of DHA with alcohols.
Scheme 18: Synthesis of dihydroxyacetone phosphate from dihydroxyacetone.
Scheme 19: Bifunctional acid–base catalyst DHA conversion into lactic acid via pyruvaldehyde or fructose forma...
Scheme 20: Catalytic one-pot synthesis of GA and co-synthesis of formamides and formates from DHA.
Scheme 21: (a) Synthesis of furan derivatives and (b) synthesis of thiophene derivative by cascade [3 + 2] ann...
Scheme 22: Brønsted acidic ionic liquid catalyzed synthesis of benzo[a]carbazole from renewable acetol and 2-p...
Scheme 23: Asymmetric hydrogenation of α-hydroxy ketones to 1,2-diols.
Scheme 24: Synthesis of novel 6-(substituted benzylidene)-2-methylthiazolo [2,3-b]oxazol-5(6H)-one from 1-hydr...
Scheme 25: ʟ-Proline-catalyzed synthesis of anti-diols from hydroxyacetone and aldehydes.
Scheme 26: C–C-bond-formation reactions of a biomass-based feedstock aromatic aldehyde (C5) and hydroxyacetone...
Scheme 27: Ethanol upgrading to C4 bulk chemicals via the thiamine (VB1)-catalyzed acetoin condensation.
Scheme 28: One-pot sequential chemoenzymatic synthesis of 2-aminobutane-1,4-diol and 1,2,4-butanetriol via 1,4...
Scheme 29: Synthesis of 1,4-dihydroxybutan-2-one by microbial transformation.
Scheme 30: Conversion of polyols by [neocuproine)Pd(OAc)]2(OTf)2] to α-hydroxy ketones.
Scheme 31: Chemoselective oxidation of alcohols with chiral palladium-based catalyst 2.
Scheme 32: Electrochemical transformation of furfural to 5-hydroxy-2(5H)-furanone (HFO).
Scheme 33: Selective hydrodeoxygenation of HFO and oxidation to γ-butyrolactone (GBL).
Scheme 34: Photosensitized oxygenation of furan towards HFO via ozonide intermediates.
Scheme 35: Conversion of furfural to HFO and MAN by using mesoporous carbon nitride (SGCN) as photocatalyst.
Scheme 36: Synthesis of HFO from furan derivatives.
Scheme 37: Photooxidation of furfural to 5-hydroxy-2(5H)-furanone (HFO).
Scheme 38: Synthesis of Friedel–Crafts indole adduct from HFO.
Scheme 39: Conversion of HFO to α,γ-substituted chiral γ-lactones.
Scheme 40: Tautomeric transformation of HFO to formylacrylic acid.
Scheme 41: Hydrolysis of HFO to succinic acid in aqueous solution.
Scheme 42: Substitution and condensation reactions of 5-hydroxy-2(5H)-furanone (HFO).
Scheme 43: (a) Conversion of HFO towards valuable C4 chemicals and (b) anodic oxidation of 5-hydroxy-2(5H)-fur...
Figure 3: Conversion of HFO towards other natural and synthetic substances.
Scheme 44: Conversion of furfural to maleic anhydride (reaction a: VOx/Al2O3; reaction b: VPO).
Scheme 45: Conversion of furfural into succinic acid.
Scheme 46: Electro‑, photo‑, and biocatalysis for one-pot selective conversions of furfural into C4 chemicals.
Scheme 47: Production route of furfural from hemicellulose.
Scheme 48: Mechanism for xylose dehydration to furfural through a choline xyloside intermediate.
Scheme 49: Conversion of furfural to furfuryl alcohol and its derivatives.
Scheme 50: Conversion of furfural to furfuryl alcohol and 3-(2-furyl)acrolein.
Scheme 51: The aerobic oxidative condensation of biomass-derived furfural and linear alcohols.
Scheme 52: The single-step synthesis of 2-pentanone from furfural.
Scheme 53: Electrocatalytic coupling reaction of furfural and levulinic acid.
Scheme 54: Conversion of furfural to m-xylylenediamine.
Scheme 55: Conversion of furfural to tetrahydrofuran-derived amines.
Scheme 56: Formation of trans-4,5-diamino-cyclopent-2-enones from furfural.
Scheme 57: Production of pyrrole and proline from furfural.
Scheme 58: Synthesis of 1‑(trifluoromethyl)-8-oxabicyclo[3.2.1]oct-3-en-2-ones from furfural.
Scheme 59: Conversion of furfural to furfural-derived diacids.
Scheme 60: A telescope protocol derived from furfural and glycerol.
Scheme 61: A tandem cyclization of furfural and 5,5-dimethyl-1,3-cyclohexanedione.
Scheme 62: A Ugi four-component reaction to construct furfural-based polyamides.
Scheme 63: One-pot synthesis of γ-acyloxy-Cy7 from furfural.
Scheme 64: Dimerization–Piancatelli sequence toward humins precursors from furfural.
Scheme 65: Conversion of furfural to CPN.
Scheme 66: Synthesis of jet fuels range cycloalkanes from CPN and lignin-derived vanillin.
Scheme 67: Solar-energy-driven synthesis of high-density biofuels from CPN.
Scheme 68: Reductive amination of CPN to cyclopentylamine.
Scheme 69: Asymmetric hydrogenation of C=O bonds of exocyclic α,β-unsaturated cyclopentanones.
Scheme 70: Preparation of levulinic acid via the C5 route (route a) or C6 route (routes b1 and b2).
Scheme 71: Mechanism of the rehydration of HMF to levulinic acid and formic acid.
Scheme 72: Important levulinic acid-derived chemicals.
Scheme 73: Direct conversion of levulinic acid to pentanoic acid.
Scheme 74: Catalytic aerobic oxidation of levulinic acid to citramalic acid.
Scheme 75: Conversion of levulinic acid to 1,4-pentanediol (a) see ref. [236]; b) see ref. [237]; c) see ref. [238]; d) see r...
Scheme 76: Selective production of 2-butanol through hydrogenolysis of levulinic acid.
Scheme 77: General reaction pathways proposed for the formation of 5MPs from levulinic acid.
Scheme 78: Selective reductive amination of levulinic acid to N-substituted pyrroles.
Scheme 79: Reductive amination of levulinic acid to chiral pyrrolidinone.
Scheme 80: Reductive amination of levulinic acid to non-natural chiral γ-amino acid.
Scheme 81: Nitrogen-containing chemicals derived from levulinic acid.
Scheme 82: Preparation of GVL from levulinic acid by dehydration and hydrogenation.
Scheme 83: Ruthenium-catalyzed levulinic acid to chiral γ-valerolactone.
Scheme 84: Catalytic asymmetric hydrogenation of levulinic acid to chiral GVL.
Scheme 85: Three steps synthesis of ε-caprolactam from GVL.
Scheme 86: Multistep synthesis of nylon 6,6 from GVL.
Scheme 87: Preparation of MeGVL by α-alkylation of GVL.
Scheme 88: Ring-opening polymerization of five-membered lactones.
Scheme 89: Synthesis of GVL-based ionic liquids.
Scheme 90: Preparation of butene isomers from GVL under Lewis acid conditions.
Scheme 91: Construction of C5–C12 fuels from GVL over nano-HZSM-5 catalysts.
Scheme 92: Preparation of alkyl valerate from GVL via ring opening/reduction/esterification sequence.
Scheme 93: Construction of 4-acyloxypentanoic acids from GVL.
Scheme 94: Synthesis of 1,4-pentanediol (PDO) from GVL.
Scheme 95: Construction of novel cyclic hemiketal platforms via self-Claisen condensation of GVL.
Scheme 96: Copper-catalyzed lactamization of GVL.
Figure 4: Main scaffolds obtained from HMF.
Scheme 97: Biginelli reactions towards HMF-containing dihydropyrimidinones.
Scheme 98: Hantzsch dihydropyridine synthesis involving HMF.
Scheme 99: The Kabachnik–Fields reaction involving HMF.
Scheme 100: Construction of oxazolidinone from HMF.
Scheme 101: Construction of rhodamine-furan hybrids from HMF.
Scheme 102: A Groebke–Blackburn–Bienaymé reaction involving HMF.
Scheme 103: HMF-containing benzodiazepines by [4 + 2 + 1] cycloadditions.
Scheme 104: Synthesis of fluorinated analogues of α-aryl ketones.
Scheme 105: Synthesis of HMF derived disubstituted γ-butyrolactone.
Scheme 106: Functionalized aromatics from furfural and HMF.
Scheme 107: Diels–Alder adducts from HMF or furfural with N-methylmaleimide.
Scheme 108: Pathway of the one-pot conversion of HMF into phthalic anhydride.
Scheme 109: Photocatalyzed preparation of humins (L-H) from HMF mixed with spoiled HMF residues (LMW-H) and fur...
Scheme 110: Asymmetric dipolar cycloadditions on HMF.
Scheme 111: Dipolar cycloadditions of HMF based nitrones to 3,4- and 3,5-substituted isoxazolidines.
Scheme 112: Production of δ-lactone-fused cyclopenten-2-ones from HMF.
Scheme 113: Aza-Piancatelli access to aza-spirocycles from HMF-derived intermediates.
Scheme 114: Cross-condensation of furfural, acetone and HMF into C13, C14 and C15 products.
Scheme 115: Base-catalyzed aldol condensation/dehydration sequences from HMF.
Scheme 116: Condensation of HMF and active methylene nitrile.
Scheme 117: MBH reactions involving HMF.
Scheme 118: Synthesis of HMF-derived ionic liquids.
Scheme 119: Reductive amination/enzymatic acylation sequence towards HMF-based surfactants.
Scheme 120: The formation of 5-chloromethylfurfural (CMF).
Scheme 121: Conversion of CMF to HMF, levulinic acid, and alkyl levulinates.
Scheme 122: Conversion of CMF to CMFCC and FDCC.
Scheme 123: Conversion of CMF to BHMF.
Scheme 124: Conversion of CMF to DMF.
Scheme 125: CMF chlorine atom substitutions toward HMF ethers and esters.
Scheme 126: Introduction of carbon nucleophiles in CMF.
Scheme 127: NHC-catalyzed remote enantioselective Mannich-type reactions of CMF.
Scheme 128: Conversion of CMF to promising biomass-derived dyes.
Scheme 129: Radical transformation of CMF with styrenes.
Scheme 130: Synthesis of natural herbicide δ-aminolevulinic acid from CMF.
Scheme 131: Four step synthesis of the drug ranitidine from CMF.
Scheme 132: Pd/CO2 cooperative catalysis for the production of HHD and HXD.
Scheme 133: Different ruthenium (Ru) catalysts for the ring-opening of 5-HMF to HHD.
Scheme 134: Proposed pathways for preparing HXD from HMF.
Scheme 135: MCP formation and uses.
Scheme 136: Cu(I)-catalyzed highly selective oxidation of HHD to 2,5-dioxohexanal.
Scheme 137: Synthesis of N‑substituted 3‑hydroxypyridinium salts from 2,5-dioxohexanal.
Scheme 138: Ru catalyzed hydrogenations of HHD to 1,2,5-hexanetriol (a) see ref. [396]; b) see ref. [397]).
Scheme 139: Aviation fuel range quadricyclanes produced by HXD.
Scheme 140: Synthesis of HDGK from HXD and glycerol as a chain extender.
Scheme 141: Synthesis of serinol pyrrole from HXD and serinol.
Scheme 142: Synthesis of pyrroles from HXD and nitroarenes.
Scheme 143: Two-step production of PX from cellulose via HXD.
Scheme 144: Preparation of HCPN from HMF via hydrogenation and ring rearrangement.
Scheme 145: Suggested pathways from HMF to HCPN.
Scheme 146: α-Alkylation of HCPN with ethylene gas.
Scheme 147: Synthesis of 3-(hydroxymethyl)cyclopentylamine from HMF via reductive amination of HCPN.
Scheme 148: Production of LGO and Cyrene® from biomass.
Scheme 149: Synthesis of HBO from LGO and other applications.
Scheme 150: Construction of m-Cyrene® homopolymer.
Scheme 151: Conversion of Cyrene® to THFDM and 1,6-hexanediol.
Scheme 152: RAFT co-polymerization of LGO and butadienes.
Scheme 153: Polycondensation of HO-LGOL and diols with dimethyl adipate.
Scheme 154: Self-condensation of Cyrene® and Claisen–Schmidt reactions.
Scheme 155: Synthesis of 5-amino-2-(hydroxymethyl)tetrahydropyran from Cyrene®.
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
- ], the enzyme-catalyzed desymmetric enantioselective reduction of 28, afforded hydroxyketone 54 in 65% yield with >99% ee and 8–9:1 dr on multigram scale [34]. Functional group transformations of 54 in four steps produced sterically hindered allyl triflate 55. By employing the palladacycle catalyst 45
- -catalyzed Suzuki cross-coupling reaction of sterically hindered substrates developed by Han [35][36][37], the coupled product 57 was obtained in a satisfactory yield (72%) from 55 and pinacol boronate 56, along with trace amounts of the double bond migrated side product 58 (57:58 = ca. 15:1). Demethylation
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].
α-Ketoglutaric acid in Ugi reactions and Ugi/aza-Wittig tandem reactions
- Vladyslav O. Honcharov,
- Yana I. Sakhno,
- Olena H. Shvets,
- Vyacheslav E. Saraev,
- Svitlana V. Shishkina,
- Tetyana V. Shcherbakova and
- Valentyn A. Chebanov
Beilstein J. Org. Chem. 2025, 21, 2021–2029, doi:10.3762/bjoc.21.157
- compared to compounds 5, which can be clearly seen in the spectrum of compound 8h with both substituted ortho-positions of the amine moiety. In our opinion, this indicates the presence of rotamerism [59][60] caused by the restricted rotation of the sterically hindered amide group. The 1H NMR spectra of
Graphical Abstract
Figure 1: Some biologically active quinoxalinone derivatives.
Scheme 1: Known multicomponent reactions of KGA.
Scheme 2: Ugi reaction involving KGA.
Scheme 3: Tandem Ugi/aza-Wittig combination involving KGA.
Figure 2: Molecular structure of 3-(4-(2-(tert-butylamino)-1-(4-methoxyphenyl)-2-oxoethyl)-5,7-dimethyl-3-oxo...
Aryl iodane-induced cascade arylation–1,2-silyl shift–heterocyclization of propargylsilanes under copper catalysis
- Rasma Kroņkalne,
- Rūdolfs Beļaunieks,
- Armands Sebris,
- Anatoly Mishnev and
- Māris Turks
Beilstein J. Org. Chem. 2025, 21, 1984–1994, doi:10.3762/bjoc.21.154
- -catalyzed propargylsilane activation pathway [26]. Therefore, the presence of a base was imperative. The only applicable base was found to be the non-nucleophilic 2,6-di-tert-butylpyridine (B1, Table 1, entries 1–6, 9–18). We also considered the structurally similar, but less sterically hindered 2,6
Graphical Abstract
Scheme 1: Alkyne arylation with diaryl-λ3-iodanes in the context of 1,2-silyl shift and potential cyclization....
Scheme 2: Competing mechanistic pathways for diene 10 and indene 11 formation.
Scheme 3: Reaction scope for the synthesis of arylated tetrahydrofurans 8. Conditions: All reactions were per...
Scheme 4: Synthesis of lactone and pyrrolidine derivatives. Conditions: ac7e = 0.1 mmol/mL. bReaction conditi...
Scheme 5: Proposed arylation–heterocyclization mechanism for internal nucleophile-containing silanes 7.
Scheme 6: Arylation of C5-chain containing acylamides 16a–c. aThe reaction was performed under modified condi...
Asymmetric total synthesis of tricyclic prostaglandin D2 metabolite methyl ester via oxidative radical cyclization
- Miao Xiao,
- Liuyang Pu,
- Qiaoli Shang,
- Lei Zhu and
- Jun Huang
Beilstein J. Org. Chem. 2025, 21, 1964–1972, doi:10.3762/bjoc.21.152
- step. However, the diastereoselective reduction of the ketone in 25 was challenging because the ketone was embedded in the concave face, which was more sterically hindered than the convex face. Common reductants, such as NaBH4, DIBAL-H, and LiAlH(Ot-Bu)3, provided product 32 with the opposite
Graphical Abstract
Scheme 1: Representative prostaglandins and general synthetic strategy toward PGDM methyl ester 4.
Scheme 2: Retrosynthetic analysis for the first generation synthesis of PGDM methyl ester 4.
Scheme 3: Synthesis of bicyclic ketal 25.
Scheme 4: Retrosynthetic analysis for the second-generation synthesis of tricyclic PGDM methyl ester 4.
Scheme 5: Asymmetric total synthesis of tricyclic-PGDM methyl ester 4.
Stereoselective electrochemical intramolecular imino-pinacol reaction: a straightforward entry to enantiopure piperazines
- Margherita Gazzotti,
- Fabrizio Medici,
- Valerio Chiroli,
- Laura Raimondi,
- Sergio Rossi and
- Maurizio Benaglia
Beilstein J. Org. Chem. 2025, 21, 1897–1908, doi:10.3762/bjoc.21.147
- ), as well as electron-donating groups like methoxy (2f), aryl/alkyl (2h,i), and alkenyl substituents (2e), were well tolerated. Notably, the sterically hindered derivative 2h was isolated with the highest yield of 87% indicating that bulky ortho-substituents on the aromatic rings do not influence the
Graphical Abstract
Scheme 1: Synthesis of vicinal diamines via imino-pinacol coupling in the presence of metal-based reductants.
Scheme 2: Light-promoted imino-pinacol coupling for the synthesis of vicinal diamines.
Scheme 3: Historical perspective on electrochemical imino-coupling protocols.
Scheme 4: Stereoselective electroreductive intramolecular imino-pinacol reaction.
Scheme 5: Scope of the imino-pinacol coupling reaction. Reaction conditions: GC electrodes, NEt4BF4 (2.6 equi...
Figure 1: X-ray determined structure of chiral piperazine 2b.
Scheme 6: Continuous flow synthesis of piperazine 2a. The yield was determined by 1H NMR spectroscopy using 1...
Scheme 7: Proposed reaction mechanism.
Scheme 8: Cyclic voltammetry investigation. Cyclic voltammetry of a 0.325 M solution of Et4NBF4 in DMF (light...
Photoswitches beyond azobenzene: a beginner’s guide
- Michela Marcon,
- Christoph Haag and
- Burkhard König
Beilstein J. Org. Chem. 2025, 21, 1808–1853, doi:10.3762/bjoc.21.143
- photoisomerisation, making it an all-visible example of a molecular motor (Scheme 29) [85]. Irradiation at 470 nm of 98-A leads to the thermally unstable 98-B, which immediately converts to the less sterically hindered 98-C. Further irradiation leads to the thermally unstable 98-D, which again converts quickly to
Graphical Abstract
Figure 1: Energy diagram of a two-state photoswitch. Figure 1 was redrawn from [2].
Figure 2: Example of the absorption spectra of the isomers of a photoswitch with most efficient irradiation w...
Scheme 1: Photoswitch classes described in this review.
Figure 3: Azoheteroarenes.
Scheme 2: E–Z Isomerisation (top) and mechanisms of thermal Z–E isomerisation (bottom).
Scheme 3: Rotation mechanism favoured by the electron displacement in push–pull systems. Selected examples of...
Figure 4: A) T-shaped and twisted Z-isomers determine the thermal stability and the Z–E-PSS (selected example...
Figure 5: Effect of di-ortho-substitution on thermal half-life and PSS.
Figure 6: Selected thermal lifetimes of azoindoles in different solvents and concentrations. aConcentration o...
Figure 7: Aryliminopyrazoles: N-pyrazoles (top) and N-phenyl (bottom).
Scheme 4: Synthesis of symmetrical heteroarenes through oxidation (A), reduction (B), and the Bayer–Mills rea...
Scheme 5: Synthesis of diazonium salt (A); different strategies of azo-coupling: with a nucleophilic ring (B)...
Scheme 6: Synthesis of arylazothiazoles 25 (A) and heteroaryltriazoles 28 (B).
Scheme 7: Synthesis of heteroarylimines 31a,b [36-38].
Figure 8: Push–pull non-ionic azo dye developed by Velasco and co-workers [45].
Scheme 8: Azopyridine reported by Herges and co-workers [46].
Scheme 9: Photoinduced phase transitioning azobispyrazoles [47].
Figure 9: Diazocines.
Scheme 10: Isomers, conformers and enantiomers of diazocine.
Scheme 11: Partial overlap of the ππ* band with electron-donating substituents and effect on the PSS. Scheme 11 was ada...
Figure 10: Main properties of diazocines with different bridges. aMeasured in n-hexane [56]. bMeasured in THF. cMe...
Scheme 12: Synthesis of symmetric diazocines.
Scheme 13: Synthesis of asymmetric diazocines.
Scheme 14: Synthesis of O- and S-heterodiazocines.
Scheme 15: Synthesis of N-heterodiazocines.
Scheme 16: Puromycin diazocine photoswitch [60].
Figure 11: Indigoids.
Figure 12: The main representatives of the indigoid photoswitch class.
Scheme 17: Deactivation process that prevents Z-isomerisation of indigo.
Figure 13: Stable Z-indigo derivative synthesised by Wyman and Zenhäusern [67].
Figure 14: Selected examples of indigos with aliphatic and aromatic substituents [68]. Dashed box: proposed π–π in...
Scheme 18: Resonance structures of indigo and thioindigo involving the phenyl ring.
Scheme 19: Possible deactivation mechanism for 4,4'-dihydroxythioindigo [76].
Scheme 20: Effect of different heteroaryl rings on the stability and the photophysical properties of hemiindig...
Figure 15: Thermal half-lives of red-shifted hemithioindigos in toluene [79]. aMeasured in toluene-d8.
Scheme 21: Structures of pyrrole [81] and imidazole hemithioindigo [64].
Figure 16: Examples of fully substituted double bond hemithioindigo (left), oxidised hemithioindigos (centre),...
Scheme 22: Structure of iminothioindoxyl 72 (top) and acylated phenyliminoindolinone photoswitch 73 (bottom). ...
Scheme 23: (top) Transition states of iminothioindoxyl 72. The planar transition state is associated with a lo...
Scheme 24: Baeyer–Drewsen synthesis of indigo (top) and N-functionalisation strategies (bottom).
Scheme 25: Synthesis of hemiindigo.
Scheme 26: Synthesis of hemithioindigo and iminothioindoxyl.
Scheme 27: Synthesis of double-bond-substituted hemithioindigos.
Scheme 28: Synthesis of phenyliminoindolinone.
Scheme 29: Hemithioindigo molecular motor [85].
Figure 17: Arylhydrazones.
Scheme 30: Switching of arylhydrazones. Note: The definitions of stator and rotor are arbitrary.
Scheme 31: Photo- and acidochromism of pyridine-based phenylhydrazones.
Scheme 32: A) E–Z thermal inversion of a thermally stable push–pull hydrazone [109]. B) Rotation mechanism favoured...
Scheme 33: Effect of planarisation on the half-life.
Scheme 34: The longest thermally stable hydrazone switches reported so far (left). Modulation of thermal half-...
Figure 18: Dependency of t1/2 on concentration and hypothesised aggregation-induced isomerisation.
Figure 19: Structure–property relationship of acylhydrazones.
Scheme 35: Synthesis of arylhydrazones.
Scheme 36: Synthesis of acylhydrazones.
Scheme 37: Photoswitchable fluorophore by Aprahamian et al. [115].
Scheme 38: The four-state photoswitch synthesised by the Cigáň group [116].
Figure 20: Diarylethenes.
Scheme 39: Isomerisation and oxidation pathway of E-stilbene to phenanthrene.
Scheme 40: Strategies adapted to avoid E–Z isomerisation and oxidation.
Scheme 41: Molecular orbitals and mechanism of electrocyclisation for a 6π system.
Figure 21: Aromatic stabilisation energy correlated with the thermal stability of the diarylethenes [127,129].
Figure 22: Half-lives of diarylethenes with increasing electron-withdrawing groups [128,129].
Scheme 42: Photochemical degradation pathway promoted by electron-donating groups [130].
Figure 23: The diarylethenes studied by Hanazawa et al. [134]. Increased rigidity leads to bathochromic shift.
Scheme 43: The dithienylethene synthesised by Nakatani's group [135].
Scheme 44: Synthesis of perfluoroalkylated diarylethenes.
Scheme 45: Synthesis of 139 and 142 via McMurry coupling.
Scheme 46: Synthesis of symmetrical derivatives 145 via Suzuki–Miyaura coupling.
Scheme 47: Synthesis of acyclic 148, malonic anhydride 149, and maleimide derivatives 154.
Figure 24: Gramicidin S (top left) and two of the modified diarylethene derivatives: first generation (bottom ...
Scheme 48: Pyridoxal 5'-phosphate and its reaction with an amino acid (top). The analogous dithienylethene der...
Figure 25: Fulgides.
Scheme 49: The three isomers of fulgides.
Scheme 50: Thermal and photochemical side products of unsubstituted fulgide [150].
Figure 26: Maximum absorption λc of the closed isomer compared with the nature of the aromatic ring and the su...
Scheme 51: Possible rearrangement of the excited state of 5-dimethylaminoindolylfulgide [153].
Figure 27: Quantum yields of ring closure (ΦE→C) and E–Z isomerisation (ΦE→Z) correlated with the increasing s...
Scheme 52: Active (Eα) and inactive (Eβ) conformers (left) and the bicyclic sterically blocked fulgide 169 (ri...
Scheme 53: Quantum yield of ring-opening (ΦC→E) and E–Z isomerisation (ΦE→Z) for different substitution patter...
Scheme 54: Stobbe condensation pathway for the synthesis of fulgides 179, fulgimides 181 and fulgenates 178.
Scheme 55: Alternative synthesis of fulgides through Pd-catalysed carbonylation.
Scheme 56: Optimised synthesis of fulgimides [166].
Scheme 57: Photoswitchable FRET with a fulgimide photoswitch [167].
Scheme 58: Three-state fulgimide strategy by Slanina's group.
Figure 28: Spiropyrans.
Scheme 59: Photochemical (left) and thermal (right) ring-opening mechanisms for an exemplary spiropyran with a...
Figure 29: Eight possible isomers of the open merocyanine according to the E/Z configurations of the bonds hig...
Scheme 60: pH-Controlled photoisomerisation between the closed spiropyran 191-SP and the open E-merocyanine 19...
Scheme 61: Behaviour of spiropyran in water buffer according to Andréasson and co-workers [180]. 192-SP in an aqueo...
Scheme 62: (left box) Proposed mechanism of basic hydrolysis of MC [184]. (right box) Introduction of electron-dona...
Scheme 63: Photochemical interconversion of naphthopyran 194 (top) and spirooxazine 195 (bottom) photoswitches...
Scheme 64: Synthesis of spiropyrans and spirooxazines 198 and the dicondensation by-product 199.
Scheme 65: Alternative synthesis of spiropyrans and spirooxazines with indolenylium salt 200.
Scheme 66: Synthesis of 4’-substituted spiropyrans 203 by condensation of an acylated methylene indoline 201 w...
Scheme 67: Synthesis of spironaphthopyrans 210 by acid-catalysed condensation of naphthols and diarylpropargyl...
Scheme 68: Photoswitchable surface wettability [194].
Figure 30: Some guiding principles for the choice of the most suitable photoswitch. Note that this guide is ve...
Structural analysis of stereoselective galactose pyruvylation toward the synthesis of bacterial capsular polysaccharides
- Tsun-Yi Chiang,
- Mei-Huei Lin,
- Chun-Wei Chang,
- Jinq-Chyi Lee and
- Cheng-Chung Wang
Beilstein J. Org. Chem. 2025, 21, 1671–1677, doi:10.3762/bjoc.21.131
- 72% yield and excellent regio- and stereoselectivity. Regarding the acceptor, compound 6 harbored two free alcohol groups at the C3 and C2 positions. Since the C3 alcohol group is less sterically hindered and exhibits better nucleophilicity, the glycosidic bond formed regioselectively at the C3
Graphical Abstract
Figure 1: Pyruvylated galactose on bacterial polysaccharides PS A1 (1), 1.15 EPS (2) and Rhizobium leguminosa...
Figure 2: (a) Oak Ridge Thermal Ellipsoid Plot view of the X-ray crystal structure of pyruvylated galactose 6...
Scheme 1: Synthesis of trisaccharide precursor 14.
Catalytic asymmetric reactions of isocyanides for constructing non-central chirality
- Jia-Yu Liao
Beilstein J. Org. Chem. 2025, 21, 1648–1660, doi:10.3762/bjoc.21.129
- , pioneered by Bringmann and co-workers [45], has proven to be a powerful approach for synthesizing axially chiral biaryls, particularly in the challenging case of sterically hindered tetra-ortho-substituted scaffolds [46][47]. In this context, α-acidic isocyanides have been successfully employed as carbon
Graphical Abstract
Figure 1: a) Common types of chirality. b) Representative functional molecules bearing non-central chirality.
Scheme 1: Construction of planar chirality.
Scheme 2: Construction of axial chirality.
Scheme 3: Construction of inherent chirality.
Scheme 4: Construction of helical chirality.
Scheme 5: CPA-catalyzed enantioselective Groebke–Blackburn–Bienaymé reaction.
Scheme 6: Construction of axially chiral 3-arylpyrroles via de novo pyrrole formation.
Scheme 7: Synthesis of atropoisomeric 3-arylpyrroles via central-to-axial chirality transfer.
Scheme 8: Dynamic kinetic resolution of bridged biaryls with α-acidic isocyanides.
Scheme 9: Desymmetrization of prochiral compounds with α-acidic isocyanides.
Photoredox-catalyzed arylation of isonitriles by diaryliodonium salts towards benzamides
- Nadezhda M. Metalnikova,
- Nikita S. Antonkin,
- Tuan K. Nguyen,
- Natalia S. Soldatova,
- Alexander V. Nyuchev,
- Mikhail A. Kinzhalov and
- Pavel S. Postnikov
Beilstein J. Org. Chem. 2025, 21, 1480–1488, doi:10.3762/bjoc.21.110
- in the reaction with sterically hindered aromatic isonitriles, such as 1-isocyano-2,4,6-trimethylbenzene and 1-isocyano-2,6-dimethylbenzene. The use of 2 equivalents of iodonium salt 1 further improved the yields of certain amides (2bb, 2bj, 2de, 2ee, 2ge and 2he), as significant amounts of unreacted
- iodonium salts with common dummy ligands such as 2,4,6-trimethoxyphenyl (TMP) [42][43], sterically hindered 2,4,6-triisopropylphenyl, and mesityl ligands. The highest selectivity was achieved using aryl(2,4,6-trimethoxyphenyl)iodonium triflates 1n–p yielding the desired amides 2ba, 2bo, and 2bp in 25–42
Graphical Abstract
Scheme 1: Background and conception.
Scheme 2: Reaction scope of iodonium salts 1 and isonitriles. aReaction conditions: isonitrile (0.2 mmol), io...
Scheme 3: Selectivity experiments and scope of unsymmetrical iodoniums salts. aReaction conditions: 2-isocyan...
Scheme 4: Proposed reaction mechanism.
Oxetanes: formation, reactivity and total syntheses of natural products
- Peter Gabko,
- Martin Kalník and
- Maroš Bella
Beilstein J. Org. Chem. 2025, 21, 1324–1373, doi:10.3762/bjoc.21.101
- cases and worked very well for both aromatic and aliphatic amides, as well as sterically hindered oxetanes. The authors further proved the robustness of this reaction by preparing various bisoxazolines 189, compounds which are common bidentate ligands in asymmetric catalysis [99]. Over the years 2019
Graphical Abstract
Figure 1: Bond lengths and bond angles in oxetane at 140 K [2].
Figure 2: Analogy of 3-substituted oxetanes to carbonyl and gem-dimethyl groups [12].
Figure 3: Use of oxetanes in drug design – selected examples.
Figure 4: Examples of oxetane-containing natural products.
Scheme 1: Synthetic strategies towards construction of the oxetane ring.
Scheme 2: Overview of intramolecular Williamson etherification and competing Grob fragmentation.
Scheme 3: Synthesis of spiro-oxetanes via 1,4-C–H insertion and Williamson etherification.
Scheme 4: Use of phenyl vinyl selenone in the synthesis of spirooxindole oxetanes.
Scheme 5: Synthesis of bicyclic 3,5-anhydrofuranoses via double epoxide opening/etherification.
Scheme 6: Preparation of spirooxetanes by cycloisomerisation via MHAT/RPC.
Scheme 7: Oxetane synthesis via alcohol C–H functionalisation.
Scheme 8: Access to oxetanes 38 from α-acetyloxy iodides.
Scheme 9: The kilogram-scale synthesis of oxetane intermediate 41.
Scheme 10: Overview of the intramolecular opening of 3-membered rings.
Scheme 11: Synthesis of 4,7-dioxatricyclo[3.2.1.03,6]octane skeletons.
Scheme 12: Silicon-directed electrophilic cyclisation of homoallylic alcohols.
Scheme 13: Hydrosilylation–iodocyclisation of homopropargylic alcohols.
Scheme 14: Cu-catalysed intramolecular O-vinylation of γ-bromohomoallylic alcohols.
Scheme 15: Cu-catalysed intramolecular cross-coupling of hydroxyvinylstannanes.
Scheme 16: Isomerisation of oxiranyl ethers containing weakly carbanion-stabilising groups.
Scheme 17: Cyclisation of diethyl haloalkoxymalonates.
Scheme 18: Synthesis of oxetanes through a 1,5-HAT/radical recombination sequence.
Scheme 19: General approach to oxetanes via [2 + 2] cycloadditions.
Scheme 20: Synthesis of tricyclic 4:4:4 oxetanes through a photochemical triple cascade reaction.
Scheme 21: Iridium-catalysed Paternò–Büchi reaction between α-ketoesters and simple alkenes.
Scheme 22: Three-step synthesis of spirocyclic oxetanes 83 via Paternò–Büchi reaction, nucleophilic ring openi...
Scheme 23: Enantioselective Paternò–Büchi reaction catalysed by a chiral iridium photocatalyst.
Scheme 24: Synthesis of polysubstituted oxetanes 92 via Cu(II)-mediated formal [2 + 2] cycloadditions.
Scheme 25: Synthesis of alkylideneoxetanes via NHC- and DBU-mediated formal [2 + 2] cycloadditions.
Scheme 26: Use of sulphur-stabilised carbanions in ring expansions.
Scheme 27: Synthesis of α,α-difluoro(arylthio)methyl oxetanes.
Scheme 28: Ring expansion in an industrial synthesis of PF-06878031.
Scheme 29: Ring contraction of triflated 2-hydroxy-γ-lactones.
Scheme 30: Ring contraction in an industrial synthesis of PF-06878031.
Scheme 31: Photochemical ring contraction of 2,5-dihydrofurans by aryldiazoacetic acid esters.
Scheme 32: Synthesis of 3-oxetanones via O-H insertion of carbenes.
Scheme 33: Synthesis of phosphonate oxetanones via gold-mediated alkyne oxidation/O–H insertion.
Scheme 34: Syntheses and common derivatisations of 3-oxetanone.
Scheme 35: SN1 substitution of 3-aryloxetan-3-ols by thiols and alcohols.
Scheme 36: Fe–Ni dual-catalytic olefin hydroarylation towards 3-alkyl-3-(hetero)aryloxetanes.
Scheme 37: Synthesis of 3-aryloxetan-3-carboxylic acids.
Scheme 38: Decarboxylative alkylation of 3-aryloxetan-3-carboxylic acids.
Scheme 39: Synthesis of 3-amino-3-aryloxetanes via photoredox/nickel cross-coupling catalysis.
Scheme 40: Intermolecular cross-selective [2 + 2] photocycloaddition towards spirooxetanes.
Scheme 41: Synthesis of 3-aryl-3-aminooxetanes via defluorosulphonylative coupling.
Scheme 42: Two-step synthesis of amide bioisosteres via benzotriazolyl Mannich adducts 170.
Scheme 43: Functionalisation of oxetanyl trichloroacetimidates 172.
Scheme 44: Synthesis of oxetane-amino esters 176.
Scheme 45: Tandem Friedel–Crafts alkylation/intramolecular ring opening of 3-aryloxetan-3-ols.
Scheme 46: Synthesis of polysubstituted furans and pyrroles.
Scheme 47: Synthesis of oxazolines and bisoxazolines.
Scheme 48: Tandem, one-pot syntheses of various polycyclic heterocycles.
Scheme 49: Synthesis of 1,2-dihydroquinolines via skeletal reorganisation of oxetanes.
Scheme 50: Synthesis of benzoindolines and 2,3-dihydrobenzofurans and their derivatisations.
Scheme 51: Synthesis of polysubstituted 1,4-dioxanes.
Scheme 52: Preparation of various lactones via ring opening of oxetane-carboxylic acids 219.
Scheme 53: Tsuji-Trost allylation/ring opening of 3-aminooxetanes.
Scheme 54: Arylative skeletal rearrangement of 3-vinyloxetan-3-ols to 2,5-dihydrofurans.
Scheme 55: Reductive opening of oxetanes using catalytic Mg–H species.
Scheme 56: Opening of oxetanes by silyl ketene acetals.
Scheme 57: Rhodium-catalysed hydroacylation of oxetanes.
Scheme 58: Generation of radicals from oxetanes mediated by a vitamin B12-derived cobalt catalyst.
Scheme 59: Reductive opening of oxetanes by B–Si frustrated Lewis pairs.
Scheme 60: Zirconocene-mediated reductive opening of oxetanes.
Scheme 61: Enantioselective syntheses of small and medium-size rings using chiral phosphoric acids.
Scheme 62: Asymmetric synthesis of 2,3-dihydrobenzo[b]oxepines catalysed by a chiral scandium complex.
Scheme 63: Enantioselective synthesis of 1,3-bromohydrins under a chiral squaramide catalysis.
Scheme 64: Enantioselective opening of 2-aryl-2-ethynyloxetanes by anilines.
Scheme 65: Ru-catalysed insertion of diazocarbonyls into oxetanes.
Scheme 66: Ring expansion of oxetanes by stabilised carbenes generated under blue light irradiation.
Scheme 67: Expansion of oxetanes via nickel-catalysed insertion of alkynyltrifluoroborates.
Scheme 68: Nickel-catalysed expansion of oxetanes into ε-caprolactones.
Scheme 69: Expansion of oxetanes via cobalt-catalysed carbonyl insertion.
Scheme 70: Gold-catalysed intramolecular 1,1-carboalkoxylation of oxetane-ynamides.
Scheme 71: Expansion of oxetanes by stabilised sulphoxonium ylides.
Scheme 72: Cu-catalysed ring expansion of 2-vinyloxetanes by diazoesters.
Scheme 73: Total synthesis of (+)-oxetin.
Scheme 74: Total synthesis of racemic oxetanocin A.
Scheme 75: Total synthesis of (−)-merrilactone A.
Scheme 76: Total synthesis of (+)-dictyoxetane.
Scheme 77: Total synthesis of ent-dichrocephone B.
Scheme 78: Total synthesis of (−)-mitrephorone A.
Scheme 79: Total synthesis of (−)-taxol.
Recent advances in oxidative radical difunctionalization of N-arylacrylamides enabled by carbon radical reagents
- Jiangfei Chen,
- Yi-Lin Qu,
- Ming Yuan,
- Xiang-Mei Wu,
- Heng-Pei Jiang,
- Ying Fu and
- Shengrong Guo
Beilstein J. Org. Chem. 2025, 21, 1207–1271, doi:10.3762/bjoc.21.98
- benzyl methyl malonates (35d, 35e) and a malonate derived from (−)-borneol (35h), were all compatible with the reaction conditions, providing the final products in moderate to good yields. However, using the sterically hindered 2-fluoromalonate as a substrate led to a reduced yield of product 35f. A
- , α-bromo ketones, and α-bromo nitriles, effectively participated in the reaction (88f–i). Even a more sterically hindered substrate also underwent successful cyclization affording 88j, thus further underscoring the robustness of this transformation. However, attempts using benzyl bromide, allyl
Graphical Abstract
Scheme 1: DTBP-mediated oxidative alkylarylation of activated alkenes.
Scheme 2: Iron-catalyzed oxidative 1,2-alkylarylation.
Scheme 3: Possible mechanism for the iron-catalyzed oxidative 1,2-alkylation of activated alkenes.
Scheme 4: A metal-free strategy for synthesizing 3,3-disubstituted oxindoles.
Scheme 5: Iminoxyl radical-promoted cascade oxyalkylation/alkylarylation of alkenes.
Scheme 6: Proposed mechanism for the iminoxyl radical-promoted cascade oxyalkylation/alkylarylation of alkene...
Scheme 7: Bicyclization of 1,n-enynes with alkyl nitriles.
Scheme 8: Possible reaction mechanism for the bicyclization of 1,n-enynes with alkyl nitriles.
Scheme 9: Radical cyclization of N-arylacrylamides with isocyanides.
Scheme 10: Plausible mechanism for the radical cyclization of N-arylacrylamides with isocyanides.
Scheme 11: Electrochemical dehydrogenative cyclization of 1,3-dicarbonyl compounds.
Scheme 12: Plausible mechanism for the dehydrogenative cyclization of 1,3-dicarbonyl compounds.
Scheme 13: Photocatalyzed cyclization of N-arylacrylamide and N,N-dimethylaniline.
Scheme 14: Proposed mechanism for the photocatalyzed cyclization of N-arylacrylamides and N,N-dimethylanilines....
Scheme 15: Electrochemical monofluoroalkylation cyclization of N-arylacrylamides with dimethyl 2-fluoromalonat...
Scheme 16: Proposed mechanism for the electrochemical radical cyclization of N-arylacrylamides with dimethyl 2...
Scheme 17: Photoelectrocatalytic carbocyclization of unactivated alkenes using simple malonates.
Scheme 18: Plausible mechanism for the photoelectrocatalytic carbocyclization of unactivated alkenes with simp...
Scheme 19: Bromide-catalyzed electrochemical trifluoromethylation/cyclization of N-arylacrylamides.
Scheme 20: Proposed mechanism for the electrochemical trifluoromethylation/cyclization of N-arylacrylamides.
Scheme 21: Visible light-mediated trifluoromethylarylation of N-arylacrylamides.
Scheme 22: Plausible reaction mechanism for the visible light-mediated trifluoromethylarylation of N-arylacryl...
Scheme 23: Electrochemical difluoroethylation cyclization of N-arylacrylamides with sodium difluoroethylsulfin...
Scheme 24: Electrochemical difluoroethylation cyclization of N-methyacryloyl-N-alkylbenzamides with sodium dif...
Scheme 25: Photoredox-catalyzed radical aryldifluoromethylation of N-arylacrylamides with S-(difluoromethyl)su...
Scheme 26: Proposed mechanism for the photoredox-catalyzed radical aryldifluoromethylation of N-arylacrylamide...
Scheme 27: Visible-light-induced domino difluoroalkylation/cyclization of N-cyanamide alkenes.
Scheme 28: Proposed mechanism of photoredox-catalyzed radical domino difluoroalkylation/cyclization of N-cyana...
Scheme 29: Palladium-catalyzed oxidative difunctionalization of alkenes.
Scheme 30: Two possible mechanisms of palladium-catalyzed oxidative difunctionalization.
Scheme 31: Silver-catalyzed oxidative 1,2-alkyletherification of unactivated alkenes with α-bromoalkylcarbonyl...
Scheme 32: Photochemical radical cascade cyclization of dienes.
Scheme 33: Proposed mechanism for the photochemical radical cascade 6-endo cyclization of dienes with α-carbon...
Scheme 34: Photocatalyzed radical coupling/cyclization of N-arylacrylamides and.
Scheme 35: Photocatalyzed radical-type couplings/cyclization of N-arylacrylamides with sulfoxonium ylides.
Scheme 36: Possible mechanism of visible-light-induced radical-type couplings/cyclization of N-arylacrylamides...
Scheme 37: Visible-light-promoted difluoroalkylated oxindoles systhesis via EDA complexes.
Scheme 38: Possible mechanism for the visible-light-promoted radical cyclization of N-arylacrylamides with bro...
Scheme 39: A dicumyl peroxide-initiated radical cascade reaction of N-arylacrylamide with DCM.
Scheme 40: Possible mechanism of radical cyclization of N-arylacrylamides with DCM.
Scheme 41: An AIBN-mediated radical cascade reaction of N-arylacrylamides with perfluoroalkyl iodides.
Scheme 42: Possible mechanism for the reaction with perfluoroalkyl iodides.
Scheme 43: Photoinduced palladium-catalyzed radical annulation of N-arylacrylamides with alkyl halides.
Scheme 44: Radical alkylation/cyclization of N-Alkyl-N-methacryloylbenzamides with alkyl halides.
Scheme 45: Possible mechanism for the alkylation/cyclization with unactivated alkyl chlorides.
Scheme 46: Visible-light-driven palladium-catalyzed radical cascade cyclization of N-arylacrylamides with unac...
Scheme 47: NHC-catalyzed radical cascade cyclization of N-arylacrylamides with alkyl bromides.
Scheme 48: Possible mechanism of NHC-catalyzed radical cascade cyclization.
Scheme 49: Electrochemically mediated radical cyclization reaction of N-arylacrylamides with freon-type methan...
Scheme 50: Proposed mechanistic pathway of electrochemically induced radical cyclization reaction.
Scheme 51: Redox-neutral photoinduced radical cascade cylization of N-arylacrylamides with unactivated alkyl c...
Scheme 52: Proposed mechanistic hypothesis of redox-neutral radical cascade cyclization.
Scheme 53: Thiol-mediated photochemical radical cascade cylization of N-arylacrylamides with aryl halides.
Scheme 54: Proposed possible mechanism of thiol-mediated photochemical radical cascade cyclization.
Scheme 55: Visible-light-induced radical cascade bromocyclization of N-arylacrylamides with NBS.
Scheme 56: Possible mechanism of visible-light-induced radical cascade cyclization.
Scheme 57: Decarboxylation/radical C–H functionalization by visible-light photoredox catalysis.
Scheme 58: Plausible mechanism of visible-light photoredox-catalyzed radical cascade cyclization.
Scheme 59: Visible-light-promoted tandem radical cyclization of N-arylacrylamides with N-(acyloxy)phthalimides....
Scheme 60: Plausible mechanism for the tandem radical cyclization reaction.
Scheme 61: Visible-light-induced aerobic radical cascade alkylation/cyclization of N-arylacrylamides with alde...
Scheme 62: Plausible mechanism for the aerobic radical alkylarylation of electron-deficient amides.
Scheme 63: Oxidative decarbonylative [3 + 2]/[5 + 2] annulation of N-arylacrylamide with vinyl acids.
Scheme 64: Plausible mechanism for the decarboxylative (3 + 2)/(5 + 2) annulation between N-arylacrylamides an...
Scheme 65: Rhenium-catalyzed alkylarylation of alkenes with PhI(O2CR)2.
Scheme 66: Plausible mechanism for the rhenium-catalyzed decarboxylative annulation of N-arylacrylamides with ...
Scheme 67: Visible-light-induced one-pot tandem reaction of N-arylacrylamides.
Scheme 68: Plausible mechanism for the visible-light-initiated tandem synthesis of difluoromethylated oxindole...
Scheme 69: Copper-catalyzed redox-neutral cyanoalkylarylation of activated alkenes with cyclobutanone oxime es...
Scheme 70: Plausible mechanism for the copper-catalyzed cyanoalkylarylation of activated alkenes.
Scheme 71: Photoinduced alkyl/aryl radical cascade for the synthesis of quaternary CF3-attached oxindoles.
Scheme 72: Plausible photoinduced electron-transfer (PET) mechanism.
Scheme 73: Photoinduced cerium-mediated decarboxylative alkylation cascade cyclization.
Scheme 74: Plausible reaction mechanism for the decarboxylative radical-cascade alkylation/cyclization.
Scheme 75: Metal-free oxidative tandem coupling of activated alkenes.
Scheme 76: Control experiments and possible mechanism for 1,2-carbonylarylation of alkenes with carbonyl C(sp2...
Scheme 77: Silver-catalyzed acyl-arylation of activated alkenes with α-oxocarboxylic acids.
Scheme 78: Proposed mechanism for the decarboxylative acylarylation of acrylamides.
Scheme 79: Visible-light-mediated tandem acylarylation of olefines with carboxylic acids.
Scheme 80: Proposed mechanism for the radical cascade cyclization with acyl radical via visible-light photored...
Scheme 81: Erythrosine B-catalyzed visible-light photoredox arylation-cyclization of N-arylacrylamides with ar...
Scheme 82: Electrochemical cobalt-catalyzed radical cyclization of N-arylacrylamides with arylhydrazines or po...
Scheme 83: Proposed mechanism of radical cascade cyclization via electrochemical cobalt catalysis.
Scheme 84: Copper-catalyzed oxidative tandem carbamoylation/cyclization of N-arylacrylamides with hydrazinecar...
Scheme 85: Proposed reaction mechanism for the radical cascade cyclization by copper catalysis.
Scheme 86: Visible-light-driven radical cascade cyclization reaction of N-arylacrylamides with α-keto acids.
Scheme 87: Proposed mechanism of visible-light-driven cascade cyclization reaction.
Scheme 88: Peroxide-induced radical carbonylation of N-(2-methylallyl)benzamides with methyl formate.
Scheme 89: Proposed cyclization mechanism of peroxide-induced radical carbonylation with N-(2-methylallyl)benz...
Scheme 90: Persulfate promoted carbamoylation of N-arylacrylamides and N-arylcinnamamides.
Scheme 91: Proposed mechanism for the persulfate promoted radical cascade cyclization reaction of N-arylacryla...
Scheme 92: Photocatalyzed carboacylation with N-arylpropiolamides/N-alkyl acrylamides.
Scheme 93: Plausible mechanism for the photoinduced carboacylation of N-arylpropiolamides/N-alkyl acrylamides.
Scheme 94: Electrochemical Fe-catalyzed radical cyclization with N-arylacrylamides.
Scheme 95: Plausible mechanism for the electrochemical Fe-catalysed radical cyclization of N-phenylacrylamide.
Scheme 96: Substrate scope of the selective functionalization of various α-ketoalkylsilyl peroxides with metha...
Scheme 97: Proposed reaction mechanism for the Fe-catalyzed reaction of alkylsilyl peroxides with methacrylami...
Scheme 98: EDA-complex mediated C(sp2)–C(sp3) cross-coupling of TTs and N-methyl-N-phenylmethacrylamides.
Scheme 99: Proposed mechanism for the synthesis of oxindoles via EDA complex.
Synthesis of β-ketophosphonates through aerobic copper(II)-mediated phosphorylation of enol acetates
- Alexander S. Budnikov,
- Igor B. Krylov,
- Fedor K. Monin,
- Valentina M. Merkulova,
- Alexey I. Ilovaisky,
- Liu Yan,
- Bing Yu and
- Alexander O. Terent’ev
Beilstein J. Org. Chem. 2025, 21, 1192–1200, doi:10.3762/bjoc.21.96
- substituted enol acetates 1a–n, possessing both electron-donating and electron-withdrawing groups, leading to the desired phosphorylation products 3a–n in good yields. Notably, sterically hindered terminal substituted enol acetates also furnished the desired products 3c–f, albeit in lower yields. The
Graphical Abstract
Scheme 1: Recent approaches for the synthesis of β-ketophosphonates by the oxyphosphorylation of unsaturated ...
Scheme 2: The scope of the discovered copper(II)-mediated phosphorylation of enol acetates.
Scheme 3: Gram-scale synthesis of 3a.
Scheme 4: Control experiments.
Scheme 5: Proposed mechanism for copper(II) mediated phosphorylation of enol acetates.
Synthesis of pyrrolo[3,2-d]pyrimidine-2,4(3H)-diones by domino C–N coupling/hydroamination reactions
- Ruben Manuel Figueira de Abreu,
- Robin Tiedemann,
- Peter Ehlers and
- Peter Langer
Beilstein J. Org. Chem. 2025, 21, 1010–1017, doi:10.3762/bjoc.21.82
- obtained for product 3e derived from 3-tolylacetylene. However, the yield for compound 3f dropped to 60% because of the more sterically hindered 2-tolylacetylene. The domino C–N cross-coupling/hydroamination reaction of 3a–h with various anilines was studied next (Scheme 2) [28][29]. The conditions were
Graphical Abstract
Figure 1: Development of drugs based on pyrrolopyrimidines: A: Cadeguomycin. B: Tubercidin. C: Toyocamycin. D...
Scheme 1: Synthesis of 3a–h. Conditions: i) Br2 (1.0 equiv), Ac2O (1.5 equiv), AcOH, 25 °C, 1 h [25]; ii) aryl ac...
Scheme 2: C–N cross-coupling/hydroamination reaction.
Scheme 3: Synthesis of 4a–m. Conditions: Pd(OAc)2 (5 mol %), DPEphos (5 mol %), K3PO4 (3 equiv), DMA, 100 °C,...
Figure 2: UV–vis absorption (left) and emission (right, λex = 300 nm) spectra of compounds 4a, 4j, 4k, 4l, an...
Silver(I) triflate-catalyzed post-Ugi synthesis of pyrazolodiazepines
- Muhammad Hasan,
- Anatoly A. Peshkov,
- Syed Anis Ali Shah,
- Andrey Belyaev,
- Chang-Keun Lim,
- Shunyi Wang and
- Vsevolod A. Peshkov
Beilstein J. Org. Chem. 2025, 21, 915–925, doi:10.3762/bjoc.21.74
- reduction with LiAlH₄, which led to a further decrease in the degree of unsaturation of the pyrazolodiazepine core, while the more sterically hindered exocyclic amide moiety remained intact. However, both reactions were accompanied by partial epimerization, and careful kinetic control was therefore required
Graphical Abstract
Figure 1: Representative diazepine-fused heterocycles.
Scheme 1: Post-Ugi synthesis of benzodiazepines and heteroaryl-fused diazepines.
Scheme 2: Synthesis of pyrazole-tethered propargylamides 15 via U4CR. Conditions: Unless otherwise specified,...
Scheme 3: Scope of the silver(I) triflate-catalyzed synthesis of pyrazolo[1,5-a][1,4]diazepines. Conditions: ...
Scheme 4: Telescope procedure for the synthesis of 16a.
Scheme 5: Tentative mechanism for the silver-catalyzed heteroannulation.
Scheme 6: Reductive post-assembly modifications of the pyrazolo[1,5-a][1,4]diazepine core. aDetermined by 1H ...
