Aldol condensation and crossed aldol
Aldehydes and Ketones · Chemistry
Study notes
Predict the crossed aldol of CH₃COCH₃ + PhCHO (dil. NaOH). Step 1: PhCHO has no α-H → can't self-condense; only acetone forms enolate. Step 2: Acetone enolate attacks PhCHO → β-hydroxy ketone. Step 3: Dehydration → PhCH=CHCOCH₃ (benzalacetone, conjugated). Step 4: One product only (Claisen–Schmidt) — no α-H on benzaldehyde prevents mixtures!