Cu(OAc) /TEMPO Cooperative Promoted Hydroamination Cyclization and Oxidative Dehydrogenation Cascade Reaction of Homopropargylic Amines.

A novel and efficient Cu(OAc) -catalyzed hydroamination cyclization and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidative dehydrogenation cascade reaction of homopropargylic amines has been developed. A library of 1,2-disubstituted pyrrole derivatives were obtained in good-to-high yields in one pot with no step-by-step feeding process. This reaction involved TEMPO playing dual roles as both an oxidative dehydrogenation reagent and a ligand. An insight into the reaction mechanism was obtained by using several analytical determination methods.