Shing Tony K M, Zhu Xue Y, Yeung Yeung Y
Department of Chemistry, The Chinese University of Hong Kong, Shatin, NT, Hong Kong (VR China).
Chemistry. 2003 Nov 21;9(22):5489-500. doi: 10.1002/chem.200305158.
An advanced pentacyclic intermediate, amenable to further elaboration into the target molecules simalikalactone D and quassimarin, has been synthesized from (S)-(+)-carvone in 21 steps and with an overall yield of 12 %. The synthesis is efficient, stereocontrolled, enantiospecific, and chirality productive, creating eight new chiral centres in pentacycle, and should provide opportunities for rapid access to simalikalactone D analogues and other bioactive quassinoids. The reaction sequence involves a regioselective bishydroxylmethylation, a stereocontrolled epoxidation, an epoxymethano-bridge formation, a 1,3-sigmatropic rearrangement and an intramolecular Diels-Alder reaction as the key steps.
一种高级五环中间体已由（S）-（+）-香芹酮经21步反应合成，总产率为12%，该中间体易于进一步转化为目标分子西玛卡内酯D和苦木素。该合成方法高效、立体可控、对映体特异性且具有手性生成能力，在五环中创造了八个新的手性中心，应为快速获得西玛卡内酯D类似物和其他生物活性苦木素类化合物提供机会。反应序列涉及区域选择性双羟甲基化、立体可控环氧化、环氧甲桥形成、1,3-西格玛重排和分子内狄尔斯-阿尔德反应作为关键步骤。
