Synthesis and Structure of 1,4-Diphenyl-3-methyl-1,2,3-triazol-5-ylidene Palladium Complexes and Application in Catalytic Hydroarylation of Alkynes
摘要:
An abnormal or mesoionic N-heterocyclic carbene (NHC), namely 1,4-diphenyl-3-methyl-1,2,3-triazol-S-ylidene (Tz), formed from 1,4-diphenyl-3-methyl-1,2,3-triazolium iodide and silver oxide, gave the corresponding silver carbene complex. The transmetalation reaction of the silver carbene complex with PdCl(2)(CH(3)CN)(2) gave a trans mononuclear complex, [(Tz)(2)PdCl(2)]. Reaction of the silver carbene complex with Pd(OAc)(2) gave an acetate-bridged binuclear complex in which the palladium had undergone a C-H insertion at the ortho position of the phenyl group attached to the triazole nitrogen (1-position). The structures of these two complexes Were established by single-crystal XRD data and spectroscopic data. The acetate complex was used as a catalyst for the stereoselective hydroarylation of alkynes.