The biomimetic cyclization of polyalkenes to steroids and their precursors continue to be of both mechanistic and synthetic interest. 1 Sulfonate esters, trisubstituted olefins , allylic alcohols , acetals and epoxides had been used as initiating groups for these cascade cyclizations. 2 Among them, epoxide has been one of the most popular initiators. 2,3-Oxidosqualene had been identified as a genuine intermediate in the conversion of squalene to lanosterol. 3 Mimicking this ...
