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

Two novel copper-catalyzed cyclization reactions involvinga remote propargylic substitution/cyclization/isomerization cascade aredisclosed. Derivatives of the seldomly studied heterocycles thieno[2,3-c]pyrrole and thieno[2,3-d]pyridazine are conveniently synthesized inmoderate to good yields from primary amines or arylhydrazinesthrough [4+1] and [4+2] reactions, respectively. Preliminary mechanis-tic experiments corroborated the occurrence of the designed cascadereactions