Cobalt-catalyzed esterification-peroxidation of α-diazoesters: access to α-acyloxy esters

A cobalt-catalyzed esterification-peroxidation was realized by a Co( ii )/TBHP system to deliver α-acyloxy esters from readily available starting materials in moderate to good yields. In this process, the O-H insertion reaction of diazo reagents, C-H activation and peroxidation were fused into a reaction system. Preliminary mechanistic studies show that a free-radical process is involved in this method. A cobalt-catalyzed three-component reaction of carboxylic acids, diazo reagents and tert -butyl hydroperoxide was realized, which afforded a straightforward synthesis of α-acyloxy esters in good yields.