To provide a method for producing a Grignard reagent from a carbon substituent-containing chlorobenzene compound and magnesium, by which the product is easily obtained by improving low reactivity of the carbon substituent-containing chlorobenzene compound at an improved reaction rate and in an improved Grignard reagent yield, to provide a composition comprising the Grignard reagent produced by the method and tetrahydropyran, and to provide a method for producing a reaction product from the Grignard reagent produced by the method.

This method for producing the Grignard reagent is characterized by reacting the carbon substituent-containing chlorobenzene compound, such as 3-methylchlorobenzene, with magnesium in tetrahydropyran as a solvent.