Stereospecific assembly of tetrahydroquinolines via tandem ring-opening/oxidative cyclization of donor-acceptor cyclopropanes with N-alkyl anilines.

An aerobic copper-catalyzed tandem reaction of N-alkyl anilines with donor-acceptor cyclopropanes is presented for the construction of tetrahydroquinolines via a sequential stereospecific ring opening and oxidative cyclization. The catalyst plays a dual role as a Lewis acid as well as being a redox catalyst. The use of air as an oxidant and the broad substrate scope are the important practical features.