PURPOSE: To obtain a new compound useful as a synthetic intermediate for various optically active compounds such as medicines, agricultural chemicals and natural products.

CONSTITUTION: The objective compound of formula I (R1 to R6 are H, alkyl, aryl o6 silyl; R1 and R2 are not simultaneously H; Ar is aryl; (n) is 1-3; R1 and R2, R2 and R3, R3 and R4, R4 and R5, R5 and R6 or R1 and R6, together with C, may form a ring), e.g. (S)(Z)-1-phenyl-[difluoro(phenyl)silyl]-2-butene. This compound of formula I is obtained by reacting substituted 1,3-butadienes of formula II with an aryl(fluoro)silane of the formula HSiFnAr3-n in the presence of a group X transition metallic catalyst having an optically active ligand (e.g. palladium chloride [(R)-N,N-dimethyl-1-(S)-2-(diphenylphosphinoferrocenyl) ethylamine] at 0-120°C.