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。
Towards EPC-syntheses of the structural class of cochleamycins and macquarimicins. Part 2: EPC-synthesis of the hydrindene subunit of the macquarimicins
The EPC-synthesis of the cis- hydrindene subunit of the macquarimicins, antibiotics with antitumour and anti-inflammatory activity, has been achieved. Desymmetrization of cis-1,4-cyclopent-2-enediol was succeeded by Diels-Alder reaction and functional group transformations to a tricyclic ketone. Regio- and stereoselective methylation via Claisen condensation and hydrogenation was followed by nucleophilic, intramolecular addition, reduction and acidic fragmentation. Further functional group transformations led to the target molecule. (c) 2007 Elsevier Ltd. All rights reserved.