**Mitsuda** reaction is the broadest and most general term for reactions leading to the formation of type A-B compounds (carboxylic acids and their ethers; catalytic systems containing metal oxides or simple and mixed bases; some ammonium salts and aminocarboxylic acids). M. r. divided into aldol and keto-enol. Diketonates and diketenes formed during the aldol process decompose into carbon monoxides, carbonyl compounds, carbonates or