Photosensitized (2+2) cycloadditions of 2,3-dimethylmaleic anhydride to 3,4-dimethyl-1-phenylphosphole

As a continuation of studies carried out in this laboratory on the properties of five-membered heterocycles such as furan, thiophene, selenophene and pyrrole as substrates for excited carbonyl compounds and for methylmaleic anhydride derivatives in photosensitized reactions, a less common substrate namely 3,4-dimethyl-1-phenylphosphole was chosen this time. The results obtained, a (2+2) cycloadduct formed between 2,3-dimethylmaleic anhydride and the heterocycle indicate that phosphole derivatives could be used as well, to initiate a new series of adducts of synthetic interest.