Unexpected results in the reaction of active methylene compounds with phenylsulfonyl-1,2-propadiene triggered by triphenylphosphine

Some unexpected phenomena were observed in the reaction of active methylene compounds with phenylsulfonyl-1,2-propadiene in the presence of Ph3P. The reaction gave three types of products: Michael adducts, rearranged adducts or a three-component adduct. It could be explained as an interesting phosphine-triggered, sulfinate anion-catalyzed reaction.