Enantioselective Total Synthesis of Octalactin A Using Asymmetric Aldol Reactions and a Rapid Lactonization To Form a Medium-Sized Ring
作者:Isamu Shiina、Minako Hashizume、Yu-suke Yamai、Hiromi Oshiumi、Takahisa Shimazaki、Yu-ji Takasuna、Ryoutarou Ibuka
DOI:10.1002/chem.200500417
日期:2005.11.4
Octalactin A, an antitumor agent containing an eight-membered lactone moiety, has been stereoselectively prepared by means of enantioselective aldol reactions of selected silyl enolates with achiral aldehydes, promoted by a chiral Sn(II) complex. The medium-sized lactone part was effectively constructed by way of a new and rapid mixed-anhydride lactonization using 2-methyl-6-nitrobenzoic anhydride
已通过手性Sn(II)配合物促进选定的甲硅烷基烯醇化物与非手性醛的对映选择性醛醇缩合反应立体选择性地制备了八元内酯A,一种含有八元内酯部分的抗肿瘤剂。通过使用催化量为4-(二甲基氨基)吡啶(DMAP)或4-(二甲基二甲基氨基)吡啶-1-氧化物(DMAPO)。仅使用5 mol%的DMAP或2 mol%的DMAPO可以迅速促进八聚actin的中等大小环的形成,这证明了新内酯化方案的显着效率。