Studies Directed to the Synthesis of the Unusual Cardiotoxic Agent Kalmanol. Enantioselective Construction of the Advanced Tetracyclic 7-Oxy-5,6-dideoxy Congener
作者:Stephane Borrelly、Leo A. Paquette
DOI:10.1021/ja9533454
日期:1996.1.1
0]octane core. In fact, ready access was gained to the α-hydroxy esters 24−27. In these advanced intermediates, it is imperative that the acetyl and carbomethoxy groups bear a trans 1,3-relationship. The neighboring OR substituent should preferably be larger than methoxy in order to guarantee 100% facial selectivity during the ensuing capture by 1 (as its lithiated derivative). This condensation leads
报道了与卡尔曼醇密切相关的高度功能化的 B-homo-C-nor grayanotoxin 的首次合成。通过利用该烯酮的迈克尔受体特性和随后从中衍生的 α,β-不饱和酯,首先从 (4R)-(+)-叔丁基二甲基甲硅烷氧基环戊烯酮开发了一种对映体控制的路线,即 4 → 7 → 8. 这些实验为双环 [3.3.0] 辛烷核心的更高级取代奠定了基础。事实上,很容易获得 α-羟基酯 24-27。在这些高级中间体中,乙酰基和甲氧基具有反式 1,3-关系是必不可少的。相邻的 OR 取代基应优选大于甲氧基,以确保在随后被 1(作为其锂化衍生物)捕获期间 100% 的面部选择性。