Synthesis of NHC Complexes by Oxidative Addition of 2-Chloro-N-methylbenzimidazole

The oxidative addition of 2-chloro-N-methylbenzimdazole to complexes of type [M(PPh₃)₄] yields after N-protonation compounds with NH,NMe-substituted NHC ligands. For M = Pd complex compound trans-[3]BF₄ was obtained, while the oxidative addition for M = Pt yielded a mixture of cis-[4]BF₄ (major) and trans-[4]BF₄ (minor).