Highly Stereoselective Total Synthesis of (+)-9-epi-Dictyostatin and (-)-12,13-Bis-epi-dictyostatin
作者:Chiara Zanato、Luca Pignataro、Andrea Ambrosi、Zhongyan Hao、Chiara Trigili、José Fernando Díaz、Isabel Barasoain、Cesare Gennari
DOI:10.1002/ejoc.201100244
日期:2011.5
The final key steps to these unnatural products were the addition of vinylzincates C10-C26 to aldehyde C1―C9 (leading surprisingly to complete stereoselectivity for the 9R-configuration in 28a and for the 9S-configuration in 12,13-bis-epimeric 28b), followed by Yamaguchi macrolactonization and global deprotection. (―)-12,13-Bis-epi-dictyostatin (1b) displayed a dramatic decrease of cytotoxicity and of
(+)-9-epi-dictyostatin (1a) 和 (-)-12,13-bis-epi-dictyostatin (1b) 的全合成,抗有丝海绵衍生的大环内酯 (-)-dictyostatin 的非对映异构体 (1) ),是通过创建 11 个立体中心和 4 个立体双键实现的,具有高水平的立体控制。来自罗氏酯的 29 步最长线性序列的产率分别为 1.53% 和 1.52%。这些非天然产物的最后关键步骤是将乙烯基锌酸盐 C10-C26 添加到醛 C1-C9(令人惊讶地导致 28a 中的 9R-构型和 12,13-双-差向异构体 28b 中的 9S-构型具有完全立体选择性) ,其次是 Yamaguchi 大环内酯化和全局脱保护。(―)-12,