The role of electron transfer processes in the photoinduced decarboxylation of alkyl pyruvates

Abstract

Irradiation of degassed solutions of alkyl pyruvates leads to the production of carbon dioxide, the yield of which is enhanced by the presence of electron acceptors, and in the case of methylviologen, the formation of reduced methylviologen is observed. A mechanism involving an electron transfer process is proposed in order to account for the decarboxylation reaction. The effect of added aromatic hydrocarbons, which act as triplet quenchers, upon the decarboxylation of methyl pyruvate is reported and was found to give enhanced carbon dioxide yields. The fact that the quenchers can enhance or ‘sensitise’ carbon dioxide production from methyl pyruvate is explained on the basis of an electron transfer mechanism.