One-pot synthesis of epoxides from benzyl alcohols and aldehydes

Abstract

A one-pot synthesis of epoxides from commercially available benzyl alcohols and aldehydes is described. The reaction proceeds through in situ generation of sulfonium salts from benzyl alcohols and their subsequent deprotonation for use in Corey–Chaykovsky epoxidation of aldehydes. The generality of the method is exemplified by the synthesis of 34 epoxides that were made from an array of electronically and sterically varied alcohols and aldehydes.

A sterically encumbered photoredox catalyst enables the unified synthesis of the classical lignan family of natural products

“…6 : 1), using a one-pot sulfonium-ylide ( 15 ) mediated epoxidation of aldehyde 16 with alcohol 14 (Table 1). 18 Sequentially, 17 was subjected to the [3 + 2] dipolar cycloaddition with 8 , and the resulting product was reduced with LiAlH 4 , providing diol 18 in 90% yield as a mixture of four inconsequential diastereomers (d.r. 3 : 3 : 2 : 1), which served as the substrate for the investigation of the proposed bis- p QM formation.…”

Synthesis of Epoxides from Alkyl Bromides and Alcohols with in Situ Generation of Dimethyl Sulfonium Ylide in DMSO Oxidations

“…2,3-Bis(4-chlorophenyl)oxirane (2b, Known Compound). 23 The title compound was obtained from 1-(bromomethyl)-4-chlorobenzene 1b (204 mg, 1 mmol, 1 equiv) as a white solid (107 mg, 0.405 mmol, 81%). mp 115−116 °C; R f = 0.56 (20:1 petroleum ether/ethyl acetate); 1 H NMR (500 MHz, CDCl 3 ) δ 7.36 (d, J = 8.5 Hz, 4H), 7.27 (d, J = 8.5 Hz, 4H), 3.80 (s, 2H); 13 C{ 1 H} NMR (125 MHz, CDCl 3 ) δ 135.4, 134.4, 129.0, 127.0, 62.4; Our 1 H and 13 C NMR data are consistent with published NMR data.…”

“…mp 115−116 °C; R f = 0.56 (20:1 petroleum ether/ethyl acetate); 1 H NMR (500 MHz, CDCl 3 ) δ 7.36 (d, J = 8.5 Hz, 4H), 7.27 (d, J = 8.5 Hz, 4H), 3.80 (s, 2H); 13 C{ 1 H} NMR (125 MHz, CDCl 3 ) δ 135.4, 134.4, 129.0, 127.0, 62.4; Our 1 H and 13 C NMR data are consistent with published NMR data. 23 2,3-Bis(3-chlorophenyl)oxirane (2c, Known Compound). 24 The title compound was obtained from 1-(bromomethyl)-3-chlorobenzene 1c (204 mg, 1 mmol, 1 equiv) as a light yellow oil (104 mg, 0.395 mmol, 79%).…”

Photoredox Generated Carbonyl Ylides Enable a Modular Approach to Aryltetralin, Dihydronaphthalene, and Arylnaphthalene Lignans

“…We sought to demonstrate further use of this reaction in target-oriented synthesis by pursuing lignans with higher oxidation states such as pycnanthulignene C ( 23 ) (Scheme a), which showed significant antimicrobial activity against a panel of drug-resistant pathogens . Starting from commercially available benzyl alcohol 24 , we generated sulfonium ylide 25 and engaged aldehyde 26 in a one-pot Johnson–Corey–Chaykovsky reaction . This afforded epoxide 27 in 98% yield and d.r.…”

“…20 Starting from commercially available benzyl alcohol 24, we generated sulfonium ylide 25 and engaged aldehyde 26 in a one-pot Johnson−Corey− Chaykovsky reaction. 21 This afforded epoxide 27 in 98% yield and d.r. 5:1, which was used as a mixture for the photoredox catalyzed [3 + 2] dipolar cycloaddition.…”