Preparation of Hydantoins by Catalytic Oxidative Carbonylation of α-Amino Amides

Hydantoins can be synthesized from the corresponding amino amides employing oxidative catalytic carbonylation using W(CO)(6) as the catalyst, I-2 as the oxidant, CO as the carbonyl source, and DBU as base. Secondary amides afford the hydantoins in good to excellent yields, which decrease as the steric bulk of the N-alkyl substituent increases.