The paper studied catalyzed insertion reaction of α-diazo-β-dicarbonyl compounds into methanol and also investigated influence factors on the reaction, for example structures of diazo and alcohols, catalyst, solvent and reaction temperature. The best results were obtained with the use of 1 mmol of diazo, 10 mmol of methanol and 1 mmol% Rh₂(OAc)₄ as a catalyst in refluxing benzene. The reaction of diazoacetoacetic esters derived from chiral alcohols with methanol catalyzed by Rh₂(OAc)₄ provided chiral α-methoxyl-β-carbonyl esters in good yields and the diastereomer ratio of the product was 3∶2～1∶1.

Key words: insertion reaction, Rh₂(OAc)₄, α-methoxyl-β-dicarbonyl compound, methanol, diazo compound