Copper-catalyzed tandem aryl-halogen hydroxylation and CH2Cl2-based N,O-acetalization toward the synthesis of 2,3-dihydrobenzoxazinones.

The concise synthesis of 2,3-dihydro-4H-benzo[e][1,3]oxazin-4-ones has been accomplished by copper-catalyzed tandem reactions of o-halobenzamides, LiOH and dichloromethane. The aryl-halogen bond hydroxylation and subsequent N,O-acetalization on CH2Cl2 are enabled under catalytic conditions which allows the generation of C(sp2)-O, C(sp3)-O and C(sp3)-N bonds to give the target products.