NEETChemistryAldehydes and Ketones
When 3-pentanone is reacted with benzaldehyde in the presence of dilute NaOH and heat, a major cross-aldol product 'P' is formed. Compound 'P' is then subjected to reductive ozonolysis ( O₃ followed by Zn/H₂O ). Identify the two final products formed after ozonolysis.
Options
- ABenzoic acid and pentanoic acid
- BBenzaldehyde and pentane-2,3-dione
- CBenzaldehyde and 3-pentanone
- DPhenylacetaldehyde and butane-2,3-dione
Correct answer
B. Benzaldehyde and pentane-2,3-dione
Step-by-step solution
The first step is a cross-aldol condensation between 3-pentanone and benzaldehyde. 3-Pentanone ( CH₃-CH₂-CO-CH₂-CH₃ ) is a symmetrical ketone with -hydrogens at C2 and C4. In the presence of dilute NaOH, it forms an enolate at C2. This enolate acts as a nucleophile and attacks the electrophilic carbonyl carbon of benzaldehyde ( C₆H₅-CHO ). Heating the reaction mixture causes the intermediate -hydroxy ketone to undergo dehydration (loss of a water molecule), forming the , -unsaturated ketone 'P'. The structure of 'P