Stereoselective Copper-Catalyzed Cross-Coupling of Aziridines with Benzimidazoles via Nucleophilic Ring Opening and C(sp2)-H Functionalization.

A copper-catalyzed cross-coupling of 2-alkyl-/2-arylaziridines with benzimidazoles is reported. The reactions involve a regiospecific ring opening of aziridines with benzimidazoles to give benzoimidazolylethylamine derivatives that lead to dehydrogenative cross-coupling between C(sp2)-H and N-H bonds to produce dihydroimidazobenzimidazoles. Optically active 2-arylaziridines can be stereoinvertivebly cross-coupled with high enantiomeric purities (77-97% ee). These aerobic catalytic systems comprise an inexpensive Cu(II) salt and PCy3 ligand at moderate temperature.