Asymmetric [3+2]Cycloannulation of Benzoxazinonesfor the Synthesis of Imidazo[5,1‑<i>c</i>]oxazinones

The asymmetric catalytic [3+2] cycloannulation of benzoxazinones with isatin-derived ketimines for the efficient construction of imidazo[5,1-<i>c</i>]oxazinones has been developed, which realized the first asymmetric reaction of benzoxazinones with excellent stereoselectivities. A series of imidazo[5,1-<i>c</i>]oxazinones containing three stereogenic centers with one <i>gem</i>-diamine-type spiro tetrasubstituted center were obtained in this organocatalytic reaction with good yields and high functional group tolerance.