5- oxoalkanoate ester acyl halide

Two other examples are of interest in that they lead to phosphonoylated oxoalkanoic esters. In the first, the acyl halide BrCOCOOEt was used as an acylating agent for the synthesis of (Et0)2P(0)CH2C0C00Et as the first stage in a preparation of phospho-nopyruvic acid The second case concerns the acylation of diethyl (difluoromethyl)-phosphonate carbanion with di- er butyl oxalate here when worked up with aqueous NaHC03-MeCN, the initial product is the hydrated form 615 of the keto ester, from which water is removed by azeotropic distillation with benzene. 

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