Reaction	Typical Reagents/Conditions	Product	Mechanistic Note	Common Pitfall
Enolate alkylation	Strong, non-nucleophilic base (e.g., LDA) to form the enolate, then an alkyl halide	New C–C bond at the α-carbon	Enolate acts as a nucleophile toward the alkyl halide’s electrophilic carbon (an SN2-like step)	Using a nucleophilic base (e.g., NaOH) instead of LDA — a nucleophilic base can attack the alkyl halide itself instead of just deprotonating
Aldol reaction	Base (e.g., NaOH) or acid catalyst	β-hydroxy carbonyl compound	Enolate (or enol) attacks the carbonyl carbon of a second molecule	Forgetting to identify the α-carbon correctly before drawing the enolate nucleophile
Aldol condensation	Aldol product, heat (or the same conditions, driven further)	α,β-unsaturated carbonyl compound	Dehydration of the β-hydroxy group, favored by conjugation with the carbonyl	Stopping analysis at the aldol product when the question asks for the condensation (dehydrated) product
Claisen condensation	Alkoxide base (e.g., NaOEt)	β-keto ester	Ester enolate attacks the carbonyl carbon of a second ester molecule, expelling alkoxide (acyl substitution, not simple addition)	Confusing this with the aldol reaction — Claisen requires an ester (a leaving group is needed for the substitution step that follows addition)

See Chapter 14 for the acidity argument (enolate resonance stabilization) and Appendix B’s section on carbonyl α-carbons for representative pKa values.

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