Copper-Mediated N‑Arylations of Hydantoins

A set of two broadly applicable procedures for the N-arylation of hydantoins is reported. The first one relies on the use of stoichiometric copper­(I) oxide under ligand- and base-free conditions and enables a clean regioselective arylation at the N3 nitrogen atom, while the second one is based on the use of catalytic copper­(I) iodide and trans-N,N′-dimethylcyclohexane-1,2-diamine and promotes arylation at the N1 nitrogen atom. Importantly, the combination of these two procedures affords a straightforward entry to diarylated hydantoins.