C4H9MgBr

C4H9MgBr is the chemical formula for butylmagnesium bromide. It is a type of Grignard reagent, which are organometallic compounds containing a carbon-magnesium bond. Grignard reagents are highly reactive and are widely used in organic synthesis as nucleophilic sources of alkyl or aryl groups.

Butylmagnesium bromide is formed by the reaction of 1-bromobutane with magnesium metal in an anhydrous ethereal solvent, typically diethyl ether or tetrahydrofuran. The reaction is exothermic and requires careful control of conditions to prevent side reactions. The general equation for its formation is C4H9Br + Mg -> C4H9MgBr.

In organic synthesis, butylmagnesium bromide is frequently employed to form new carbon-carbon bonds. It reacts with electrophiles such as aldehydes, ketones, esters, and epoxides to produce alcohols or other functionalized organic molecules. For instance, its reaction with an aldehyde will yield a secondary alcohol after workup. Its strong nucleophilicity and basicity make it a versatile reagent for constructing complex organic structures.

Like other Grignard reagents, butylmagnesium bromide is sensitive to moisture and air, reacting readily with water and oxygen. Therefore, it must be handled under an inert atmosphere, such as nitrogen or argon, and with anhydrous solvents. Its decomposition products can include butane and magnesium hydroxide or bromide salts.