PURPOSE: To obtain the title silane useful as a plant protectant in high yields by hydrosilylating a specified compound and reacting the product without isolation with a methylmagnesium halide, etc.

CONSTITUTION: A compound of the formula: H2C=CH-CH2-R3 [wherein R3 is a group represented by formula I (wherein R4 and R5 are each H or a halogen; and (o) and (p) are each 0, 1 or 2) or the like] is reacted with dichloromethylsilane in the presence of a catalyst (e.g. hexachloroplatinic acid) suitable for the hydrosilylation reaction, and the obtained intermediate is reacted without isolation with a methylmagnesium halide and an arylmagnesium halide of formula II [wherein R1 and R2 are each H, a halogen, a 1-4C alkyl(thio), a 1-4C (halo)alkyl or the like; X is CH=CH or N=CH or S; (m) and (n) are each 0, 1 or 2; and Hal is a halogen] to obtain the purpose compound of formula III.