Grignard reaction of methylmagnesium bromide with CO2 gives which carboxylic acid after workup?

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Multiple Choice

Grignard reaction of methylmagnesium bromide with CO2 gives which carboxylic acid after workup?

Grignard reagents react with carbon dioxide to form a carboxylate that, after acidic workup, becomes a carboxylic acid. The key is that the R group attached to the magnesium ends up as the one-carbon substituent in the resulting acid, giving R-CO2H. Here, the Grignard is methylmagnesium bromide, so R is CH3. After reaction with CO2 and the acid workup, the product is acetic acid (CH3CO2H). The other acids would require different Grignard reagents: propionic acid would come from an ethyl Grignard (CH3CH2MgBr), benzoic acid from a phenyl Grignard (C6H5MgBr), and formic acid would require R = H, which isn’t a typical Grignard reagent.

Grignard reagents react with carbon dioxide to form a carboxylate that, after acidic workup, becomes a carboxylic acid. The key is that the R group attached to the magnesium ends up as the one-carbon substituent in the resulting acid, giving R-CO2H.

Here, the Grignard is methylmagnesium bromide, so R is CH3. After reaction with CO2 and the acid workup, the product is acetic acid (CH3CO2H). The other acids would require different Grignard reagents: propionic acid would come from an ethyl Grignard (CH3CH2MgBr), benzoic acid from a phenyl Grignard (C6H5MgBr), and formic acid would require R = H, which isn’t a typical Grignard reagent.

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