I2-Promoted Multicomponent Dicyclization and Ring-Opening Sequences: Direct Synthesis of Benzo[e][1,4]diazepin-3-ones via Dual C-O Bond Cleavage.

A novel and efficient formal [4 + 2+1] annulation of aryl methyl ketones and 2-aminobenzyl alcohols for the synthesis of benzo[e][1,4]diazepin-3-ones is reported. This reaction successfully affords diverse seven-membered ring lactams via dual C-O bond cleavage. A preliminary mechanistic study showed that a multicomponent dicyclization and ring-opening sequence might occur, with the introduction of methyl sulfide proposed as the last step. This efficient strategy with mild reaction conditions and a broad substrate scope has potential applications in chemistry and medicine.