Abstract: Aliphatic, aromatic and vinylic acid chlorides were converted into the corresponding a-diazoketones in synthetically useful yields by reaction with N- isocyanotriphenyliminophosphorane followed by treatment of the resulting N-unsubstituted a- ketohydrazidoyl chlorides with triethylamine in the presence of a catalytic amount of p- toluenesulfonyl chloride. Key words: acyl chlorides, a-diazoketones, N- ...