Electrochemical oxidation of tetracyclones and tetraphenylthiophene-S-oxide

The electrooxidative behaviour of tetraphenylcyclopentadienone (tetracyclone) and a number of its substituted derivatives have been studied by cyclic voltammetry. Preparative electrooxidation reactions have been found for the tetracyclones to yield the corresponding α-pyrones as major product from an oxygen insertion reaction; while in contrast, under similar conditions the sulfoxy analogue, tetraphenylthiophene-S-oxide, is oxidized to (Z)-diphenacylstilbene with loss of the sulfur-function from the heteroaromatic ring.