Lactone Carboxylic Acids. IV. Reaction of Ethyl Chloroarylpyruvate with Ethyl Malonate

The condensation of ethyl chloroarylpyruvate (Ⅰ) with ethyl malonate in the presence of sodium ethoxide afforded γ-aryl-α,β-dicarbethoxy-⊿(β),γ-butenolide. On the basis of the chemical and spectral evidences, the structure of the product (II) has been elucidated. This reaction provides new routes to α,β-dicarboalkoxy-γ-butyrolactones and/or to γ-ketocarboxylic acids.