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 N-3 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 N-1 nitrogen atom. Importantly, the combination of these two procedures affords a straightforward entry to diarylated hydantoins.