Photoinduced electron transfer reactions of aryl benzyl sulfides promoted by 2,4,6-triphenylpyrilium tetrafluoroborate (TP+BF4 -)

Abstract

Photocatalytic electron transfer reactions of aryl benzyl sulfides using 2,4,6-triphenylpyrilium tetrafluoroborate (TP+BF4 -) resulted in the oxidation of these sulfides to the corresponding sulfoxides and also in most cases in the C-S bond cleavage of them along with formation of aromatic aldehydes. In these reactions, the formation of sulfide radical cation has been proposed, which undergoes either oxidation to the corresponding sulfoxide or C-S bond cleavage to the formation of aromatic aldehydes. The further oxidation of sulfoxides to sulfones has not been observed. The influence of substrate structures on the reaction pathways as well as the role of O2 in this respect is discussed.