The present invention provides a method of kinetic optical resolution of carboxylic acid derivatives using specific optically active catalysts. A racemic or diastereomeric mixture of carboxylic acid derivatives of the formula (A) is reacted with a nucleophile in the presence of an optically active catalyst to form an optically active nucleophile derivative of the formula (B). The catalyst is an optically active compound represented by the formula (C) or (D) [wherein R.sup.1 is a substituted or unsubstituted, saturated or unsaturated, straight-chain, branched or alicyclic aliphatic hydrocarbon group which can have a heteroatom, R.sup.2 is ethyl or vinyl, and R.sup.5 is hydrogen or methoxy respectively]. ##STR00001##