Metalated epoxides as carbenoids. Competing C–H and CC insertion in α-alkoxy epoxide systems

In a reinvestigation of the reactivity of carbenoids derived from epoxides, we studied the factors that could influence the chemoselectivity of the carbenoid insertion into vicinal C–H or CC bond in cyclic α-alkoxy epoxides bearing an alkenyl side chain. This reaction gives access to bi- or tricyclic systems, respectively.