Among the following statements, which accurately describes reducing esters?

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Multiple Choice

Among the following statements, which accurately describes reducing esters?

The key idea is how strongly each reducing agent donates hydride to esters. LiAlH4 is a very powerful hydride donor and can attack the carbonyl carbon of an ester, displacing the alkoxide and forming an aldehyde intermediate, which is then reduced again to yield a primary alcohol after workup. In contrast, NaBH4 is milder and typically reduces aldehydes and ketones well but does not reduce esters under ordinary conditions. So esters are converted to alcohols with LiAlH4, while NaBH4 generally leaves esters untouched. The possibility of forming alkanes from esters with LiAlH4 isn’t correct under standard conditions—the product of ester reduction by LiAlH4 is an alcohol, not an alkane. This makes the statement describing LiAlH4 reducing esters to alcohols and NaBH4 generally not reducing esters the best description.

The key idea is how strongly each reducing agent donates hydride to esters. LiAlH4 is a very powerful hydride donor and can attack the carbonyl carbon of an ester, displacing the alkoxide and forming an aldehyde intermediate, which is then reduced again to yield a primary alcohol after workup. In contrast, NaBH4 is milder and typically reduces aldehydes and ketones well but does not reduce esters under ordinary conditions. So esters are converted to alcohols with LiAlH4, while NaBH4 generally leaves esters untouched. The possibility of forming alkanes from esters with LiAlH4 isn’t correct under standard conditions—the product of ester reduction by LiAlH4 is an alcohol, not an alkane. This makes the statement describing LiAlH4 reducing esters to alcohols and NaBH4 generally not reducing esters the best description.

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