Enantioselective Total Synthesis of (+)-Neostenine.

A chirality transfer approach using acyclic polyol intermediates for the synthesis of (+)-neostenine (1) has been developed. The sequential Overman/Claisen rearrangement of an allylic 1,2-diol was especially useful, installing two contiguous stereocenters with complete diastereoselectivity in a one-pot sequence. The SmI2 -mediated cyclization and the subsequent chemoselective reduction of a lactam moiety accomplished the first enantioselective total synthesis of (+)-neostenine (1).