Facile C-N Bond Cleavage Promoted by Cuprous Oxide: Formation of C-C-Coupled Biimidazole from Its Methylene-Bridged Congener

The methylenebis(N-alkylimidazolium) halides are converted to dialkylbiimidazoles by cuprous oxide wit concurrent C-N bond cleavage and C-C bond formation. This unusual C-N bond cleavage is proposed to involve a Cu(I)-NHC (N-heterocyclic carbene) complex. The reaction is unique, as it involves C-H bond activation, C-N bond cleavage, and C-C bond formation.