Synthesis of Cyclopalladated Phenyl Imidazoline-Carbene Complexes and Catalytic Study in Suzuki Reaction

Abstract

The amido alcohols compounds 1a and 1b were synthesized from commercially available 3-nitrobenzoic acid or benzoic acid and (S)-2-amino-3-methyl-1-butanol at room temperature. The amido alcohols, when treated with excess thionyl chloride, followed by p-toluidine, gave the phenyl imidazoline compounds 2a and 2b. Cyclopalladated phenyl imidazoline-carbene complexes 3a and 3b were obtained by the reaction of phenyl imidazolines 2a and 2b with Pd(OAc) 2 /LiCl followed by treatment with 1,3-dibenzyl-benzimidazolium chloride. All the complexes 3a and 3b were characterized by 1 H NMR, 13 C NMR, MS and elemental analysis. In the crystal of complex 3a, the compound was assembled to a chain supramolecular structure by the intermolecular hydrogen bonds. And complex 3a presented good catalytic effect on Suzuki reaction.