A simple synthesis of (+)- and (−)-alkaloid 241D and C-4 epimers

Abstract

An enantioselective preparation of both enantiomers of alkaloid 241D 1 and its C-4 epimer is reported. This simple and concise synthesis, seven steps from pent-3-en-2-one, involves a highly diastereoselective Mannich-type cyclisation as the key step.