Synthesis of the Trans-Syn-Trans Perhydrobenzo[f]chromene Ring System

A stereoselective synthesis of the trans-syn-trans perhydrobenzo[f]chromene skeleton is presented. The target compound 3 was achieved in six steps starting from the (S)-(+)-Wieland-Miescher ketone. Key steps include the sp2 alkylation at the a-carbon of an unsaturated ketone, Birch-type reductive alkylation, and an acid-catalyzed cyclization.