PURPOSE: To obtain a new compound useful as an intermediate for ferroelectric liquid crystal displaying materials and antiinflammatory agents and analgesics.

CONSTITUTION: This compound is represented by formula I (R1 alkyl; R3 is at-alkyl; * denotes asymmetric carbon atom), e.g. (S)-2-[4-(t-butyloxymethyl) phenyl]propionic acid. The compound of formula I is obtained by hydrolyzing an optically active aromatic group-substituted alkanoic ester of formula II (R2 is a monovalent organic group) with a base in a solvent.