Organophotocatalytic oxidation of alcohols to carboxylic acids

A sustainable photochemical protocol for the oxidation of alcohols to ketones and carboxylic acids has been developed by using 2,4,6-triphenylpyrylium tetrafluoroborate (TPPT) as organophotocatalyst and molecular oxygen as oxidant under visible light irradiation. The key reactive oxygen species, superoxide (O-2(center dot-)) for the first oxidation step from alcohol to aldehyde and singlet oxygen (O-1(2)) for the second oxidation step from aldehyde to carboxylic acid, were generated successfully by electron transfer and energy transfer pathways, respectively. A range of primary and secondary alcohols were converted to the corresponding carboxylic acids or ketones, and the optimized reaction conditions were applied to the synthesis of benzocoumarin.

Automated summary

A sustainable photochemical protocol for the oxidation of alcohols to ketones and carboxylic acids was developed using a visible-light organophotocatalyst and molecular oxygen as the oxidant. Superoxide and singlet oxygen were successfully generated through electron transfer and energy transfer pathways, respectively, for the two oxidation steps. Various alcohols were converted into the corresponding ketones or carboxylic acids, and the optimized reaction conditions were applied to the synthesis of benzocoumarin.