PURPOSE: To produce the titled compound in high stereospecificity and yield with simple operation, by reacting an inexpensive optically active lactic acid ester with a phenolic compound in the presence of a phosphite and a specific compound such as dialkylazodicarboxylate.

CONSTITUTION: An optically active lactic acid ester of formula I (R1 is univalent ester-forming group removable from the compound of formula III under weakly basic W acidic condition) is made to react with a phenolic compound of formula II (R2 is H or 1W5 substituent groups which do not inhibit the reaction of the compound of formula I with the compound of formula II) in the presence of a compound selected from trialkylphosphine, trialkylphosphite, triarylphosphine and triarylphosphite and a compound selected from dialkylazodicarboxylate and diarylazodicarboxylate to obtain the ester of formula III, from which the optically active 2-phenoxypropionic acid of formula IV is isolated.