Copper-Catalyzed Nitrene Transfer as a Tool for the Synthesis of N-Substituted 1,2-Dihydro- and 1,2,3,4-Tetrahydropyridines

The sequential reaction of two different furans and PhI=NTs produces 1,2-dihydropyridines in a quantitative manner in the presence of Tp(Br3)Cu(NCMe) (Tp(Br3) = hydrotris(3,4,5-tribromopyrazolyl)borate) as the catalyst under very mild conditions. The use of a furan and ethyl vinyl ether with PhI=NTs has led to the corresponding 1,2,3,4-tetrahydropyridine.