PRODUCTION OF OPTICALLY ACTIVE CARBOXYLIC ACID DERIVATIVE

PROBLEM TO BE SOLVED: To produce an optically active carboxylic acid derivative useful as an intermediate or the like for producing an N,N-substituted cyclic amine derivative useful as a medicine by a method excellent in industrial productivity by utilizing a specific reagent for resolution. SOLUTION: A (±)-carboxylic acid derivative of formula I (R1 is H, a halogen or the like; R2 is a lower alkyl or a lower cycloalkyl; n is 0 or an integer of 1-5; m is 0 or an integer of 1-6); [e.g. (±)-4-cyano-5-methyl-4-phenylhexane] is subjected to optical resolution by using one kind of an optically active substance of an amine of formula II (R3 is H, a halogen or the like), [e.g. (-)-1- phenylethylamine] to provide the objective optically active carboxylic acid derivative of formula III. For example, 0.1-5.0 equivalent of the compound of formula II is used based on the carboxylic acid derivative of formula I to provide a diastereomer salt, and one hardly soluble salt is isolated. The isolated diastereomer salt is treated with an acid and the treated diastereomer salt is subjected to back extraction to provide the objective optically active carboxylic acid derivative of formula III.