Enantioselective Allyltitanation. Synthesis of (-)-Slaframine

An enantioselective synthesis of the indolizidine alkaloid (-)-slaframine from aldehyde 1 is reported. The stereogenic centers at C-1 and C-8a are introduced by an enantioselective allyltitanation and a Mitsunobu reaction. Reductive double cyclization of the acyclic compound (-)-10 affords the bicyclic skeleton of (-)-slaframine.