GENERATION OF ACYL RADICALS FROM 2-NAPHTHYL THIOESTERS

A series of S-2-naphthyl thioesters were synthesized from the corresponding carboxylic acids or acid chlorides. Irradiation of these thioesters in the presence of a hydrogen source (i.e., 1,4-cyclohexadiene) generated the corresponding aldehydes. In this fashion, primary, secondary, tertiary, and aryl carboxylic acids were converted to the aldehydes in high yields. Intramolecular radical cyclization reactions support the hypothesis that the reaction proceeds via the formation of acyl radicals. The formation of aldehydes was not perturbed by possible Norrish Type II reactions.