School of Chemical Sciences, University of Auckland, Auckland, New Zealand.
J Org Chem. 2011 Nov 18;76(22):9417-28. doi: 10.1021/jo201729t. Epub 2011 Oct 20.
The spirastrellolides are a family of potent antimitotic agents isolated from the marine sponge Spirastrella coccinea . Synthetic studies toward the DEF bis-spiroacetal core of spirastrellolide B are reported. A modular approach was pursued by the use of two dithiane disconnections to enable a highly convergent synthesis. The ease of lithiation and nucleophilicity of these 2-substituted-1,3-dithianes were investigated during the course of the synthesis, and the alkylations were found to proceed most efficiently at elevated temperatures. Formation of the [5,6,6]-bis-spiroacetal ring system was achieved via a double dithiane deprotection/spiroacetalization strategy.
螺旋甾内酯是一组从海洋海绵螺旋星藻中分离出来的强效抗有丝分裂剂。本文报道了对螺旋甾内酯 B 的 DEF 双螺环缩醛核心进行的合成研究。通过使用两种二硫戊烷断裂来实现高度汇聚的合成，采用模块化方法。在合成过程中研究了这些 2-取代-1,3-二硫戊烷的锂化和亲核性，发现烷基化在高温下进行得最有效。[5,6,6]-双螺环缩醛环系统的形成是通过双二硫戊烷脱保护/螺环缩醛化策略实现的。
