Copper-Catalyzed [4+1] and [4+2] Reactions through Tandem ­Remote Propargylation/Cyclization/Isomerization with an Amine or a Hydrazine

Abstract

AbstractTwo novel copper-catalyzed cyclization reactions involving a remote propargylic substitution/cyclization/isomerization cascade are disclosed. Derivatives of the seldomly studied heterocycles thieno[2,3-c]pyrrole and thieno[2,3-d]pyridazine are conveniently synthesized in moderate to good yields from primary amines or arylhydrazines through [4+1] and [4+2] reactions, respectively. Preliminary mechanistic experiments corroborated the occurrence of the designed cascade reactions.