Cycloaddition of Spiroepoxycyclohexa-2,4-dienones, Radical Cyclization and 1,3-Acyl Shift in Excited State: Aromatics to Sterpuren-4-one

A stereoselective route to sterpuren-4-one from a simple aromatic precursor is presented. Oxidative dearomatization, π4s + π2s cycloaddition of 6,6-spiroepoxycyclohexa-2,4-dienones with ethyl acrylate, radical cyclization and 1,3-acyl shift in excited state are the important aspects of our approach. An interesting effect of a remote substituent on radical cyclization has also been presented.

本文报道了由简单芳香族前体合成sterpuren-4-酮的立体选择性路线。该方法的核心环节包括氧化脱芳构化、6,6-螺环氧环己-2,4-二烯酮与丙烯酸乙酯发生的π4s+π2s环加成反应、自由基环化以及激发态下的1,3-酰基迁移。此外，本文还展示了远程取代基对自由基环化反应的有趣影响。