Photochemical coupling reaction of phenacyl benzoate with acetone to form 1,4-dicarbonyl compound enabled by charge transfer

Photolysis of phenacyl benzoates tethered with a phenol or anisole in acetone resulted in the formation of 1,4-dicarbonyl compounds, coupling products of the phenacyl moiety with acetone. The reaction occurs via electron and/or proton transfer from a triplet exciplex, leading to the formation of a phenacyl radical, which then adds to the enol form of acetone. The reaction also occurs in intermolecular fashion with external electron donors.