中文摘要：

本研究工作建立了一种合成环巴胺ABC环的有效方法。该方法的亮点在于扁桃酸缩醛介导的稠环酮（±）-4的拆分及IBX-介导的化合物12的多位点同步氧化。所建立的光学纯关键中间体（＋）-4和2的简便合成方法为进一步合成具有生物活性的各种C-去甲-D-高甾烷甾体生物碱（如环巴胺）提供了可行性。

英文摘要：

A practical approach to the synthesis of the A, B and C-ring subunit of cyclopamine has been developed. This synthetic tactic highlights the utility of mandelate acetal-mediated resolution of the fused ring ketone （±）-4 and IBX-mediated oxidation cascades from 12 to 9. The availability of advanced intermediates from enantiomerically pure （＋）-4 and 2 could provide efficient access to bio- logically active and structurally diverse C-nor-D-homo-steroidal alkaloids such as cyclopamine.