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Given the following information, why don't chemists just use butyllithium itself to deprotonate the aldehyde or ketone and form the enolate?

Enolates are frequently formed by treating an aldehyde or ketone with LDA. However, the LDA must first be generated by reacting diisopropylamine with butyllithium.

Answer 1

#Bu^(n)Li# is a powerful base, but also a powerful nucleophile.

#Bu^(n)Li# and #MeLi# might add to the carbonyl carbon, rather than deprotonating the #alpha# hydrogen. On the other hand, #LDA# is a powerful base, but an indifferent nucleophile. The action of #LDA# on the #alpha#-hydrogen will generate the enolate.

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Answer 2

Delilah Anderson

Butyllithium is too strong of a base and can cause overreaction or side reactions in many cases. It is also highly reactive and can be difficult to control, leading to issues with selectivity and yield in the reaction.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.