The Synthesis of Multifunctionalized 1,3-Oxazin-4-ones from Donor–Acceptor Cyclopropanes

A series of electronically diverse imines were found to readily react with various donor–acceptor cyclopropyl acid chlorides, with complete regioselectivity, to form 1,3-oxazin-4-ones in moderate yields (25–48% over two steps). Select oxazinones underwent a base induced rearrangement to afford the corresponding cycloheptene-fused oxazinones in good yields (up to 70%).