Synthesis of 9-oxa-noradamantane derivative, an aesthetically pleasing ‘oxa-basket’
摘要:
A simple protocol for the synthesis of an aesthetically pleasing 'oxa-basket' (5-methoxy-2,8,13-trioxapentacyclo[7.2.1.1.(5,12)0.(4,11)0(6,10)]tridecane-3,7-dione), possessing 9-oxa-noradamantane core, is described. The readily available diquinane based dichloro bis-gamma-lactone precursor upon treatment with MeSO3H furnished dichloro 'oxa-basket' which was dechlorinated using TBTH/AIBN to obtain the title compound. The key role of the chlorines was demonstrated by replacement with hydrogen or allyl substituents which redirects the cascade to simple hydrolysis products. (C) 2009 Elsevier Ltd. All rights reserved.
报道了从三环衍生物9开始的基于二喹烷的构象约束对称双-γ-内酯的两种非对映异构体的有效立体选择性合成。关键步骤涉及通过二酮的原位形成水合物形成环氧化物的分子内开环,从而导致四环半缩醛10,这在碱性过氧化氢裂解条件下直接导致外-羟基双-γ-内酯衍生物2和4。。通过氢氧化锂介导的S N转化为内羟基双γ-内酯衍生物1和3二甲磺酸酯7中的2个置换,或更快速地,通过偏苯三酸酯21通过碱性H 2 O 2介导的裂解。