α-Pyranones; I. Reaction of 4-ethoxy and 4-chloromethylene-2-phenyl-5(4H)-oxazolone with ethyl 3-oxo-4-(triphenylphosphoranylidene)butyrate: A new synthesis of 2H-pyran-2-one compounds

Article abstract of DOI:10.1055/s-1992-26133

The reaction of 4-ethoxymethylene-5(4H)-oxazolone (2a) with ethyl 3-oxo-4-(triphenylphosphoranylidene)butyrate (1) affords ethyl 3-benzoylamino-2-oxo-6-triphenylphosphoranylidenemethyl-2H-pyran-5-cah boxylate (3). Starting from the corresponding 4-chlorom