Photoredox Generated Carbonyl Ylides Enable a Modular Approach to Aryltetralin, Dihydronaphthalene, and Arylnaphthalene Lignans
作者:Edwin Alfonzo、Alexandra M. Millimaci、Aaron B. Beeler
DOI:10.1021/acs.orglett.0c02286
日期:2020.8.21
A one-pot synthesis of dihydronaphthalenes and arylnaphthalenes from epoxides and common dipolarophiles is described. The reaction proceeds through photoredox activation of epoxides to carbonyl ylides, which undergo concerted [3 + 2] dipolar cycloaddition with dipolarophiles to provide tetrahydrofurans or 2,5-dihydrofurans. In the same flask, acid promoted rearrangement affords densely functionalized
The photochemistry of 2,3-bis(p-methoxyphenyl)oxirane: trapping of a C–C cleaved intermediate in an electron-transfer sensitised process
作者:Paul Clawson、Patricia M. Lunn、Donald A. Whiting
DOI:10.1039/c39840000134
日期:——
2,3-Bis(p-methoxyphenyl)oxirane (6) rearranges, with C–O cleavage, to the carbonyl compounds (8) and (9) on irradiation, direct or triplet sensitised, and thermally: in contrast C–C cleavage is observed with dicyanoanthracene as electron-transfersensitiser, and the resulting intermediate can be trapped by dipolarophiles in synthetically useful reactions.