(+)-Brefeldin A was synthesized through an efficient route, which features (1) construction of the five-membered ring from a Crimmins aldol via tandem Li-I exchange and carbanion-mediated cyclization with concurrent removal of the chiral auxiliary, (2) introduction of the lower side chain (C10 to C16) via a Rh-catalyzed Michael addition of a vinyl boronic acid, (3) stereoselective reduction of the C7 ketone with SmI(2), and (4) a 2-methyl-6-nitrobenzoic anhydride-mediated (Shiina) lactonization.
(+)-Brefeldin A 是通过高效路线合成的,其特点包括:(1) 通过Crimmins
酯交换 Aldo 反应,经由连续的
锂-
碘交换和介导的环状
羧酸盐形成五元环;(2) 利用
铑催化的
乙烯基硼酸的迈克尔加成引入邻近的侧链(C10至C16);(3) 利用
钐碘化物对C7
酮进行选择性还原;(4) 利用
2-甲基-6-硝基苯甲酸酐介导的Shiina环化反应完成缩合。