Trapping rhodium carbenoids with aminoalkynes for the synthesis of diverse N-heterocycles

A convergent approach for the synthesis of diverse N-heterocycles is described. The reaction involves trapping of diazo-derived rhodium carbenoids with gold activated aminoalkynes, and accommodates both the donor/acceptor (D/A) as well as acceptor/acceptor (A/A) diazo carbonyls. Mechanistic investigations indicate that the Rh(II)/Au(I) catalyzed reaction of aminoalkynes with D/A diazos is concerted, while the reaction with A/A diazo is stepwise and proceeds with carbene N–H insertion and a subsequent Conia-ene cyclization.