Reaction of 3-hydroxy-1,2,3,4-tetrahydroquinoline-2,4-diones with ethyl(triphenylphosphoranylidene)acetate

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.