General method for the expedient synthesis of salt-free diorganozinc reagents using zinc methoxide.

The effect of counterions has a great impact on the solubility of magnesium salts in Et2O. By reacting Zn(OMe)2 with readily available Grignard reagents, it was possible to induce the complete precipitation of magnesium salts and then obtain salt-free diorganozinc reagents after centrifugation/filtration. This practical method to generate dialkylzinc reagents as well as mixed diorganozinc reagents was successfully tested in various catalytic enantioselective reactions, proving the purity of the product and its synthetic usefulness.