Chelated [3,3]-rearrangements of difluoroallylic alcohols
摘要:
Whereas the lithium enolates of acetate and propionate esters of difluoroallylic alcohols fragment rapidly, even at -78 degrees C, methoxy-and benzyloxy-acetates form chelated enolates which undergo smooth [3,3]-rearrangement as their silyl ketene acetals. The latent ketone function can be revealed under mild conditions (MeOH, SOCl2) to afford very highly functionalised CF2 compounds. (C) 1997 Elsevier Science Ltd.
Synthesis of α-hydroxy-β,β-difluoro-γ-ketoesters via [3,3]sigmatropic rearrangements
作者:Michael J. Broadhurst、Samantha J. Brown、Jonathan M. Percy、Michael E. Prime
DOI:10.1039/b004766j
日期:——
Readily available γ,γ-difluorinated allylic alcohols obtained from trifluoroethanol were esterified efficiently. Exposure to strong base (LDA) afforded the ester enolates, in which chelation both controlled configuration and stabilised against fragmentation, which were trapped as their silyl ketene acetals. Rearrangement occurred to afford base-sensitive acid products. Esterification under mild conditions
Chelated [3,3]-rearrangements of difluoroallylic alcohols
作者:M.J. Broadhurst、J.M. Percy、M.E. Prime
DOI:10.1016/s0040-4039(97)01315-4
日期:1997.8
Whereas the lithium enolates of acetate and propionate esters of difluoroallylic alcohols fragment rapidly, even at -78 degrees C, methoxy-and benzyloxy-acetates form chelated enolates which undergo smooth [3,3]-rearrangement as their silyl ketene acetals. The latent ketone function can be revealed under mild conditions (MeOH, SOCl2) to afford very highly functionalised CF2 compounds. (C) 1997 Elsevier Science Ltd.