An Improved Method for γ-Carboxylation of β-Diketones. Synthesis of 4-Alkyl-3,5-Dioxohexanoic Acids and 5-Alkyl Derivatives of Triacetic Acid Lactone

Abstract

γ-Carboxylation of β-diketones, 1, can be improved using samples containing 100% of ketoenol tautomers, 3, prepared by mild hydrolysis of the corresponding copper(II) complexes 2. Cyclization of the so formed 4-alkyl-3,5-dioxohexanoic acids, 4, affords 5-alkyl-4-hydroxy-6-methyl-2-pyrones, 5.