The reaction of alkylchloropyruvate (1) with sodiomalonate gave γ-alkyl-α, β- dialkoxycarbonyl-Δ β, γ-butenolide (2), which led to γ-ketocarboxylic acid (3). The reaction of 1 with sodioacetoacetate gave 2-alkyl-5-methylfuran-3, 4-dicarboxylate (6) via the intermediate 2-alkyl-3-hydroxy-5-methyl-2, 3-dihydrofuran-3, 4-dicarboxylate (5). It has been shown unambiguously that the carbanions of both sodiomalonate and sodioacetoacetate ...
