To provide a method for easily producing an optically active α- hydroxyketal useful as an intermediate for a physiologically active substance such as a medicine or an agrochemical, or a fine chemical compound in high yield by oxidizing a specific enol ether compound in the presence of a specified optically active manganese complex catalyst.

(A) A compound of formula I {R5 is a 1-6C alkyl; R6 and R7 are each a 1-6C alkyl [substituted by a group (Z) of a 1-4C alkyl, a 1-4C alkoxy, etc.], a phenyl [substituted by a group (Z)], or R6 and R7 may be bonded to each other to form a 4-8C member ring} is oxidized in the presence of an optically active catalyst of formula II [R1 to R4 are each H, a 1-4C alkyl (substituted by a 1-4C alkyl or a halogen), a phenyl (substituted by a halogen, a 1-4C alkyl, etc.), or two of the R1 to R4 may form a 4-8C member ring by being combined with each other; R is same as the R1, etc.; X- is an anionic pair capable of forming a salt; Y is H, a halogen, a 1-4C alkyl, etc.; a binaphthyl group may be a racemic body or an optically active substance] to provide the objective compound of formula III [R8 is same as the R5; (*) represents that the absolute configuration of the C is R or S] in the method for producing an optically active α-hydroxyketal.