Grignard addition to formaldehyde using phenylmagnesium bromide yields which product after workup?

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Multiple Choice

Grignard addition to formaldehyde using phenylmagnesium bromide yields which product after workup?

Explanation:
Grignard reagents act as nucleophiles that attack the carbonyl carbon of aldehydes. With formaldehyde, the attack introduces the Grignard’s R group (here, phenyl) onto that carbon, giving an alkoxide after addition. Upon acidic workup, this alkoxide is protonated to reveal a primary alcohol with the R group attached to a CH2 unit: R–CH2OH. Since the Grignard is phenylmagnesium bromide, R is phenyl, so the product is benzyl alcohol (phenyl–CH2OH). That’s why benzaldehyde would not be correct in this case, because loading formaldehyde with a Grignard reagent pushes the reaction all the way to the primary alcohol, not to an aldehyde. Ethanol would arise from a methyl Grignard, and phenol would require a different transformation altogether.

Grignard reagents act as nucleophiles that attack the carbonyl carbon of aldehydes. With formaldehyde, the attack introduces the Grignard’s R group (here, phenyl) onto that carbon, giving an alkoxide after addition. Upon acidic workup, this alkoxide is protonated to reveal a primary alcohol with the R group attached to a CH2 unit: R–CH2OH. Since the Grignard is phenylmagnesium bromide, R is phenyl, so the product is benzyl alcohol (phenyl–CH2OH).

That’s why benzaldehyde would not be correct in this case, because loading formaldehyde with a Grignard reagent pushes the reaction all the way to the primary alcohol, not to an aldehyde. Ethanol would arise from a methyl Grignard, and phenol would require a different transformation altogether.

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