Partially solvated alkylmagnesium chlorides in toluene

Toluene solutions of alkylmagnesium chlorides partially solvated by diethyl ether were investigated. Primary and secondary alkyl chlorides can be converted into Grignard reagents in good yields in the presence of small amounts of ether (less than one mole per mole of halide). Tertiary chlorides form only monosolvated organomagnesium compounds. Ultrasound accelerates the process. The reagents obtained are heterogeneous, but the solubilities of the partially solvated complexes in toluene are fairly high. Some of the reagents disproportionate to magnesium chloride and the dialkylmagnesium. The extent of disproportionation decreases with an increase in the concentration of the reagent or in the steric requirements of the alkyl moiety.