gem-Difluoromethylation of α- and γ-ketoesters: preparation of gem-difluorinated α-hydroxyesters and γ-butyrolactones
作者:Manat Pohmakotr、Duanghathai Panichakul、Patoomratana Tuchinda、Vichai Reutrakul
DOI:10.1016/j.tet.2007.06.096
日期:2007.9
PhSCF2SiMe3 has been demonstrated as difluoromethyl carbanion synthon (−CF2H). It reacts chemoselectively with α- and γ-ketoesters at the keto group in the presence of a catalytic amount of TBAF in THF to give the corresponding α-hydroxy ester adducts as well as γ-gem-difluorophenylsulfanylmethylated-γ-butyrolactones in good yields. Reductive cleavage of the phenylsulfanyl group of these products employing
PhSCF 2森达3已被证明是二氟甲基碳负离子合成子(- CF 2 H)。在催化量的TBAF在THF中的存在下,它与酮基上的α-和γ-酮酸酯发生化学选择性反应,以高收率得到相应的α-羟基酯加合物以及γ-宝石-二氟苯基硫烷基甲基化-γ-丁内酯。使用Bu 3 SnH / AIBN对这些产物的苯基硫烷基进行还原性裂解,可以以良好的收率得到相应的宝石-二氟甲基化的α-羟基酯和γ-丁内酯。