Abstract The Wittig reaction of 3-hydroxy-1, 2, 3, 4-tetrahydroquinoline-2, 4-diones 2 with ethyl (triphenyl-phosphoranylidene) acetate 3 proceeds stereoselectively to give E-4- carbethoxymethylene-1, 2, 3, 4-tetra-hydro-2-quinolones 4, which were hydrolyzed to corresponding acids 6 Butenolides 5 were detected and, in some cases, isolated as a minor product of the Wittig reaction.
