Grignard reagents require anhydrous conditions and what solvent?

• A. Anhydrous ether solvents such as diethyl ether or THF
• B. Water
• C. Methanol
• D. Acetonitrile

Answer: (A)

Grignard reagents act like highly reactive organomagnesium carbanions and are extremely eager to grab a proton or be oxidized. That sensitivity means they must be formed and used in strictly anhydrous conditions. The solvent needs to coordinate to the magnesium to stabilize the RMgX species; ether solvents supply lone pairs on oxygen that can chelate the Mg and keep the reactive Grignard solvated and active. Diethyl ether and THF are the classic choices because they stabilize the magnesium center effectively, enabling the carbon–magnesium bond to behave as a nucleophile or base in subsequent steps. Protic solvents like water or methanol would protonate and destroy the Grignard, and while acetonitrile can coordinate to magnesium, it doesn’t provide the same beneficial stabilization as ethers and can hinder reactivity. So the required solvent is anhydrous ether solvents such as diethyl ether or THF.