Regio- and Diastereoselective Access to 4‑Imidazolidinones via an Aza-Mannich Initiated Cyclization of Sulfamate-Derived Cyclic Imines with α‑Halo Hydroxamates

An efficient regio- and diastereoselective cyclization of sulfamate-derived cyclic imines with unsubstituted or monosubstituted α-halo hydroxamates is developed under mild conditions. This reaction proceeds smoothly under transition-metal-free conditions via a domino aza-Mannich addition/intramolecular nucleophilic substitution sequence, providing a convenient route to access 2-monosubstituted and 2,5-disubstituted 4-imidazolidinones. Notably, the products were obtained with single trans-isomers in moderate to excellent yields.