An Enantioselective Total Synthesis of (+)- and (−)-Saudin. Determination of the Absolute Configuration
作者:Robert K. Boeckman,、Maria del Rosario Rico Ferreira、Lorna H. Mitchell、Pengcheng Shao
DOI:10.1021/ja017194i
日期:2002.1.1
A short efficient enantioselective synthesis of both (+)- and (-)-saudin, a naturally occurring hypoglycemic diterpene, is described. This synthesis establishes the absolute configuration of natural (-)-saudin for the first time. The key steps include the enantioselective construction of a dimethyl Hagemann's ester by an asymmetric Michael reaction and establishment of the key 1,3 disposed quaternary
描述了 (+)- 和 (-)-saudin(一种天然存在的降血糖二萜)的短有效对映选择性合成。这种合成首次建立了天然 (-)-saudin 的绝对构型。关键步骤包括通过不对称迈克尔反应对二甲基哈格曼酯进行对映选择性构建,以及通过新型 Ti (IV) 促进的克莱森重排建立关键的 1,3 位四元中心。多环缩酮骨架的组装很可能在动力学控制下通过在最后阶段通过氧鎓离子中间体形成 C1 氧-C7 键而进行。