PURPOSE: To obtain the subject compd. being L-isomer with high optical yield from an easily available raw material by a method wherein after a specified phosphine compd. and a specified substd. vinyl compd. are radical-polymerized, the intermediate product is reacted with HCl, etc.

CONSTITUTION: At first, a compd. of formula I (wherein R1 and R2 are each H, a 1-6C alkyl, etc.; n is 0 or 1; m is 0 when R2≠H; R1 is not H when n=1) is reacted with a compd. of formula II [wherein R'3 is a (substd.) 1-6C alkyl or a (substd.) 1-10C acyl; R7 is H or a (substd.) 1-5C alkyl] in the presence of catalytic amt. of a radical forming agent to obtain an intermediate of formula III. Then, the intermediate is reacted with HCl, an alkali hydroxide, an alkali alcoholate, NH3, H-Ala-Ala-OR6 (wherein R6 is a 1-6C alkyl and benzyl) or H-Ala-Leu-OR6 to obtain an aimed compd. of formula IV [wherein R3 is R'3 or H; R4 is a (substd.) 1-hydroxy-1-6C alkyl].