Abstract The generation of a pseudo-diatomic species “RP S”(thioxophosphane) has been achieved from the reaction of triphenyldibromophosphorane (4) with bis ( triphenylmethylmercapto) phosphines (7). This reactive intermediate was trapped via Diels- Alder addition to 1, 3-dienes producing cyclic thiophosphoranes 13, 15, 16 and 18 along with two acyclic species, 14 and 17.
