(2-Ethoxy-2-oxoethylidene)triphenylphosphorane(Carbethoxymethylene)triphenylphosphorane(Carbethoxymethylidene)triphenylphosphorane(Ethoxycarbonylmethylidene)triphenylphosphoraneEthyl (triphenylphosphoranylidene)acetateTriphenylcarbethoxymethylenephosphorane