Regioselective synthesis of 2-iminooxazinones from dioxinones and carbodiimides

Iminooxazinones are readily formed via microwave heating of dioxinones in the presence of carbodiimides. Unsymmetrically substituted carbodiimides generally react with high or complete regioselectivity, allowing for assembly of the target ring systems with full control of substitution pattern under convenient conditions.