PURPOSE: To obtain the subject compound useful as a synthetic intermediate for medicines, agricultural chemicals and fine chemicals in one-stage reaction in good selectivity by reacting 2-propynyl carbonates with a carbonyl compound in the presence of a Pd catalyst-tin chloride.

CONSTITUTION: A compound of formula I (R1 and R2 are H, 1-8C alkyl, aryl, etc.) is made to react with a compound of formula II (R3 is 1-8C alkyl or aryl; R4 is H, 1-8C alkyl or aryl or R3 and R4 together form alkylene) in the presence of a Pd catalyst-tin chloride in a solvent (e.g. 1,3-dimethylimidazolidinone) at 0-150°C to afford the objective substance of formula III. The compounds of formulas I and II are used at 1:1 molar ratio. The Pd catalyst is used in a molar amount of 0.01-10 times based on the compound of formula II and the tin chloride is used in a molar amount of 0.2-20 times based on the compound of formula II. A ligand such as a phosphine is preferably added to the reactional system.