Synthesis of 1,4-diazepinone derivatives a domino aza-Michael/S2 cyclization of 1-azadienes with α-halogenoacetamides

A novel cyclization of α-halogenoacetamides with 1-azadienes has been developed for the efficient preparation of monocyclic 1,4-diazepinones in one step under transition metal-free conditions. Various α-halogenoacetamides and 1-azadienes are well tolerated and give the desired products in good to excellent yields. This cyclization also demonstrates potential synthetic utility on a gram-scale and further transformation. A novel cyclization of N -alkoxy α-halogenoacetamides with N -sulfonyl-1-aza-1,3-butadienes has been developed for the efficient preparation of 1,4-diazepinones in one step under transition metal-free conditions.