Why does the Grignard reagent of CH3I can only be prepared using diethyl ether as solvent but there is no reaction when using THF?
MeMgI is usually prepared in ether, but it can also be prepared in THF. However, magnesium iodide is sparingly soluble in THF, so RMgI reagent in THF should not be very concentrated, so that no MgI2 precipitate forms.