TEMP and copper cocatalyzed oxygenation of ketones with molecular oxygen: chemoselective synthesis of alpha-ketoesters

A novel and practical method for the synthesis of alpha-ketoesters through TEMP and copper cocatalyzed chemoselective oxidative coupling of commercially available methyl ketones with alcohols is developed. Mild conditions and broad substrate scope make this chemistry an efficient tool for the late-stage modification of bioactive compounds. Detailed mechanistic studies demonstrate a novel mechanism involving an organocatalytic cycle and SET process. The oxygenation process with molecular oxygen enables this transformation.