Photorearrangement of allyl diphenyl phosphate via possible type-II reaction and phosphoranyl 1,3-biradicals

Abstract A Norrish type-II reaction is proposed for the photorearrangement of allyl diphenyl phosphate to ortho -allylphenyl phenyl phosphate. In contrast to the type-II mechanism in carbonyl compounds, the reaction is postulated to proceed through a five-membered transition state to produce a phosphoranyl 1,3-biradical which subsequently rearranges to the observed product.