New,Diastereoselective One‐Pot Synthesis of Tetrasubstituted Hydantoins

An effective route to hydantoins is described, based on the 2 : 1 : 1 addition of arylsulfonyl isocyanates, dialkyl acetylenedicarboxylates, and dialkyl trialkylsilyl phosphites. The resulting tetrasubstituted, stable hydantoins 4 / 4′ (Table) were obtained in excellent yields, and their structures were corroborated spectroscopically (IR, ¹H‐, ¹³C‐, ³¹P‐NMR, EI‐MS) and by elemental analyses. A plausible mechanism for this type of cyclization is proposed (Scheme 2).