Base promoted aerobic oxidation of alcohols to corresponding aldehydes or ketones catalyzed by CuCl/TEMPO

An efficient and selective aerobic oxidation of alcohols to the corresponding aldehydes or ketones in the ionic liquid [bmim][PF6] using CuCl/TEMPO/base catalytic system has been developed. Base, as the co-catalyst, accelerates the oxidation procedure remarkably. A possible mechanism for oxidation of alcohols promoted by bases was supposed. Bases with high coordinating ability show high promoting effect and might have dual roles: as a base to deprotonate the alcohol and as a ligand to coordinate with copper(I) salt, bases with low coordinating ability might act only as a base to deprotonate the alcohol and show moderate promoting effect.