Two different approaches to the enantioselective syntheses of (+)-sedamine and (-)-allosedamine are described, both using the Sharpless asymmetric epoxidation as the key step. Regioselective reduction of epoxides, chemoselective oxidation of alcohols, ring-closing metathesis, and nucleophilic displacements were the other key steps employed.
alkaloids - asymmetric synthesis - regioselective reduction - ring-closing metathesis
