EtMgBr

Ethylmagnesium bromide, EtMgBr, is an organomagnesium compound commonly used as a Grignard reagent in organic synthesis. It is typically prepared by reacting ethyl bromide with magnesium metal in a strictly anhydrous ether solvent, such as diethyl ether or THF, under an inert atmosphere. In solution, EtMgBr behaves as a polar, highly reactive complex stabilized by coordination to the ether solvent.

EtMgBr is highly reactive toward moisture and oxygen, and thus is prepared and used under strictly dry conditions. It is typically stored and handled in dry glassware at low temperatures or under inert gas. The ether solvent stabilizes the reactive Mg center, enabling the reagent to function as a carbon nucleophile and base in a range of transformations.

Core reactivity includes: hydrolysis to give ethane and magnesium bromide hydroxide; quenching with carbon dioxide to form propionic acid after acidic workup; reaction with aldehydes and ketones to yield primary, secondary, or tertiary alcohols after workup (the ethyl group from EtMgBr adds to the carbonyl carbon, increasing the carbon skeleton); and reaction with epoxides to afford longer-chain alcohols. It can also participate in nucleophilic additions to formaldehyde and other carbonyl compounds, enabling diverse carbon–carbon bond formation.

Applications are broad in synthetic organic chemistry, including assembly of extended alcohols, carboxylic acids via CO2 fixation, and various alkylation reactions. Safety considerations center on moisture/air sensitivity, flammability, and the need for strict inert-atmosphere handling.