Ruthenium-Catalyzed One Pot Three Component Substrate Controlled Site Selective Annulation Reaction via Cascade Dehydrogenative Pathway for 4H-Benzo[d][1,3]oxazin-4-one Derivatives

A ruthenium-catalyzed chelation-assisted substrate-controlled site selective one pot three component cascade dehydrogenative annulation reaction is reported. The developed methodology proceeds for biologically active 4Hbenzo[d] [1,3] oxazin-4-one derivatives by the nucleophilic addition of amines followed by coupling of diphenyl acetylene. In addition to providing excellent yields of products, the method is also regioselective. This new protocol has been demonstrated to have an easy access to a variety of dihydroisoquinoline benzamide derivatives. The chemo-selectivity has been explained by a DFT study.