CuX2-mediated oxybromination/aminochlorination of unsaturated amides: synthesis of iminolactones and lactams

We report herein a CuX2-mediated halocyclization of gamma,delta-unsaturated amides for the synthesis of functionalized iminolactones and lactams respectively under mild reaction conditions. Mechanism studies indicated that N-attack cyclization was via a radical route while oxycyclization was via a nucleophilic attack on the activated C-C bond.