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.