Regioselective synthesis of (E)-3-[2-(arylmethylene)-1-(arylsulfonyl)hydrazino]-2-propenoates via the reaction of arylsulfonyl hydrazones and alkyl propiolates in the presence of triphenylphosphine

A regioselective method for the synthesis of (E)-3-[2-(arylmethylene)-1-(arylsulfonyl)hydrazino]-2-propenoates is described. The reaction takes place between arylsulfonyl hydrazones and alkyl propiolates in the presence of triphenylphosphine as the catalyst.