A Thio-Diels−Alder Route to the Azocine Ring System. Total Synthesis of (±)-Otonecine
作者:Edwin Vedejs、Rocco J. Galante、Peter G. Goekjian
DOI:10.1021/ja973464e
日期:1998.4.1
A sulfur-based strategy for synthesis of otonecine is described. Key steps include the thio-Diels−Alder trapping of thioketone 8 by the Danishefsky diene, followed by conversion into the enone 27 and internal Michael addition to afford bicyclic thioaminal 28. Selective C−S bond cleavage was achieved after conversion to alcohol 36 or its derivatives 38, resulting in the azocine ring system. The successful
描述了一种用于合成奥托新碱的硫基策略。关键步骤包括由Danishefsky 二烯对硫酮8 进行硫代-Diels-Alder 捕获,然后转化为烯酮27 和内部迈克尔加成以提供双环硫胺醛28。在转化为醇36 或其醇后实现选择性C-S 键裂解。衍生物 38,导致 azocine 环系统。成功的路线是从 40b 通过 49a 和亚砜消除到烯烃 50a。最终转化为奥托新碱是通过 56 的低温渗透、关键的 OsO4 介导的二醇 58 氧化为酮醇 60/61 以及伯吉斯消除为 68/69 来完成的。合成后期的几种中间体主要以双环价键互变异构体形式存在,这是奥托新星环系统的特征。