Approach to the Homoerythrina Alkaloids Using a Tandem N-Alkylation/Azomethine Ylide Cycloaddition
作者:William H. Pearson、Jeffrey E. Kropf、Allison L. Choy、Ill Young Lee、Jeff W. Kampf
DOI:10.1021/jo0703799
日期:2007.5.1
Synthetic efforts toward the homoerythrina alkaloids 1−3 are described. Two separate model systems guided the pivotal [3 + 2] azomethine ylide cycloaddition cascade to form the A−C rings of these alkaloids. The cycloaddition precursors 63 and 68, prepared in nine and ten steps, respectively, from alkyne 47, each contain an enolizable ketone, a tethered electrophile, and an electron-poor dipolarophile
朝homoerythrina生物碱合成工作1 - 3进行了描述。两个独立的模型系统引导关键的[3 + 2]甲亚胺叶立德环加成级联反应形成这些生物碱的A-C环。由炔烃47分别以九步法和十步法制备的环加成前体63和68各自包含可烯醇化的酮,束缚的亲电子体和贫电子的双亲亲电子体。用甲锡胺17加热63和68,生成脱甲氧基秋水mer碱65和脱甲氧基秋水仙碱70。,是分子内甲亚胺叶立德环加成产物。随后安装的C-3甲氧基尝试1 - 3也有所说明。