Reaction between Dialkyl Acetylenedicarboxylates and Arylsulfonyl Isocyanates in the Presence of Trialkyl Phosphites: A Simple and Efficient Synthesis of Tetrasubstituted Hydantoins

Abstract An effective route to novel hydantoins is described. This involves reaction of dialkyl acetylenedicarboxylates and arylsulfonyl isocyanates in the presence of trialkyl phosphites. Stable crystalline phosphorus ylides are obtained in excellent yields from the 1:1:2 addition reaction between trialkyl phosphites and dialkyl acetylenedicarboxylates in the presence of arylsulfonyl isocyanates. These hydantoin-containing phosphoranes exist in solution as a mixture of two geometrical isomers as a result of restricted rotation around the carbon-carbon double bond resulting from conjugation of the ylide moiety with the adjacent carbonyl group.