Combination of CuBr2 and multi-functional ligand bearing a bidentate nitrogen unit, a phenol group and a TEMPO moiety as catalyst for the aerobic oxidation of primary alcohols

Abstract

A novel ligand (L) bearing a bidentate nitrogen ligand unit, a phenol group and a TEMPO moiety has been synthesized. The ligand has been used as a catalyst precursor for the copper-catalyzed aerobic oxidation of alcohols to aldehydes, in the presence of K2CO3. The complex obtained in-situ from the ligand with copper(II) bromide (CuBr2) in a 2:1 acetonitrile/water mixture, selectively catalyzes the aerobic oxidation of primary benzylic and allylic alcohols to their corresponding aldehydes, and no over-oxidation products are detected. Keywords: Alcohols, Aerobic oxidation, Multifunctional ligand, TEMPO, Bidentate nitrogen ligand