Catalytic, Asymmetric Synthesis of 1,4-Benzoxazinones: A Remarkably Enantioselective Route to α-Amino Acid Derivatives from o-Benzoquinone Imides

Cycloaddition of o‐benzoquinone imides with chiral ketene enolates derived from cinchona alkaloid catalysts is the basis of a catalytic asymmetric synthesis of 1,4‐benzoxazinones and 1,4‐benzoxazines. The resulting cycloadducts can be derivatized in situ to provide α‐amino acid products in good‐to‐excellent yields with very high enantioselectivities (see scheme; CAN=ceric ammonium nitrate, Nu=nucleophile).