Chiral acetylenic sulfoxides in organic synthesis: Secondary amine cyclization and total synthesis of (S)-(−)-carnegine

Abstract

Michael addition of secondary amines 1b–1g onto chiral acetylenic sulfoxides 2 followed by acid induced cyclization afforded structures of tetrahydroisoquinoline skeleton in high to moderate diastereoselectivity. Optical pure (S)-(−)-carnegine has been synthesized.