To obtain the subject compound useful as a raw material for perfume, agrochemical, medicine, etc., by reacting an aldehyde or a ketone with an alcohol in the presence of a specific catalyst.

An aldehyde (e.g. formaldehyde) or a ketone (e.g. methyl ethyl ketone) of Formula I [R1 and R2 are each H, a (substituted) 1-20C hydrocarbon] is reacted with an alcohol of the formula R3-OH [R3 is a (substituted) 1-20C monofunctional hydrocarbon] or HO-R4-OH (R4 is an alkylene) (e.g. methanol) in the presence of an organotin compound of a salt of a (substituted) maleic acid or its ester [preferably a dialkyltin maleate (e.g. dimethyltin maleate), a dialkyltin maleic acid ester salt (e.g. dimethyltin maleic acid methyl ester)] at 100-760 mmHg at -30 to 200°C to give the objective compound of formula III. The amount of the catalyst used is 1-500 ppm based on the solution of the reaction mixture.