Ligand-Free Copper(I)-Catalyzed Benzylic Acyloxylation of 2-Alkylpyridines under Aerobic Conditions.

A ligand-free copper(I)-catalyzed benzylic acyloxylation of 2-alkylpyridines with carboxylic acids was realized by using 1.0 atm of O2 as a green oxidant. The transformation provided a facile access to a wide range of N-heterocyclic esters through C-O bond formation, with broad substrate scope and good functional group tolerance. Preliminary mechanistic investigations showed that this protocol included a radical process.