Reagent-Directed Allylic Quadraselection. Chemoselective <i>Anti</i>- and <i>Syn</i>-Lawton S<sub>N</sub>2′ Methylation of Seven-Membered Epoxyvinylsulfones
作者:Wan Pyo Hong、Ahmad El-Awa、Philip L. Fuchs
DOI:10.1021/ja9017557
日期:2009.7.8
Methods have been developed for regio- and stereoselective 1,4-syn or 1,4-anti methylation of seven-membered epoxyvinylsulfones. 1,4-Syn addition is achieved via the combination of Me2Zn and catalytic Li2CuCl4, a hitherto unexplored reagent combination. The complementary 1,4-anti addition relies on Cu(I) catalyzed methyl Grignard addition or (CH3)(3)Al assisted CH3Cu addition. The methods described were assayed on four diastereomeric stereodiads and on their parent epoxide.