Regiospecific Formal [3+2] Annulations of α‐keto Sulfines and N‐Substituted Thioureas

Abstract

A series of 2,4-dithiohydantoins were synthesized regiospecificlly from various phenacyl sulfoxides bearing 1-methyl-1H-tetrazole and Nsubstituted thioureas in moderate to excellent yields. The proposed mechanism involved the generation of α-sulfines from sulfoxides through thermolytic elimination, carbonphilic attack of sulfines by substituted thioureas, and dehydration condensation. The current method provides a safe strategy for the preparation of 2,4-dithiohydantoins.