UTA OCHEM LAB FINAL QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS) ALREADY
GRADED A+
aldol condensation reaction summary Ans✓✓✓combination of two
aldehyde or ketone molecules with the loss of water through elimination.
An electron rich alpha carbon atom of an enolizable aldehyde or ketone
molecules attacks the electron poor carbonyl carbon of the second
aldehyde or ketone molecule through nucleophilic addition.
Can be catalyzed by an acid or base
aldol condensation reagents Ans✓✓✓needs a strong base for high conc.
of enolates.
8 M of NaOH or 33% NaOH is catalytic enough
Bases used but produce low conc. of enolates; NaOH or KOH
aldol condensation intermediate step Ans✓✓✓alpha-hydroxyaldehyde
or alpha-hydroxyketone
-may not happen if aryl group present at the end of the ketone because
dehydration happens more readily.
aldol condensation product Ans✓✓✓alpha, beta-unsaturated carbonyl
, piperonalpinacolone (mp 96 C)
4,4-dimethyl-1-(3,4-methylenedioxyphenyl)-1-penten-3-one.
aldol condensation (Acidic Conditions) Ans✓✓✓Oxygen of ketone or
aldehyde deprotonate acid e.g. H-Cl
aldol condensation enolate Ans✓✓✓resonance stabilized, negative
charge can be carried on either the carbon or oxygen
it is ambidentate; can do O-attack or C-attack.
sp3 hybridized C-H Ans✓✓✓pka 50
sp2 hybridized C-H Ans✓✓✓pka about 20
same as acetone
Mechanism of Base-Catalyzed Aldol Condensation Ans✓✓✓1. Base
abstracts alpha proton from the enolizable carbonyl giving the
nucleophilic enolate.
2. Electron rich carbon (nucleophile) attacks electron poor carbon on the
second aldehyde/ketone.
3.The remaining alpha proton is acidic enough to form conjugatively
stabilized alpha, beta- unsaturated carbonyl system that makes process
energetically favorable (Exo-, spontaneous)
DETAILED ANSWERS (VERIFIED ANSWERS) ALREADY
GRADED A+
aldol condensation reaction summary Ans✓✓✓combination of two
aldehyde or ketone molecules with the loss of water through elimination.
An electron rich alpha carbon atom of an enolizable aldehyde or ketone
molecules attacks the electron poor carbonyl carbon of the second
aldehyde or ketone molecule through nucleophilic addition.
Can be catalyzed by an acid or base
aldol condensation reagents Ans✓✓✓needs a strong base for high conc.
of enolates.
8 M of NaOH or 33% NaOH is catalytic enough
Bases used but produce low conc. of enolates; NaOH or KOH
aldol condensation intermediate step Ans✓✓✓alpha-hydroxyaldehyde
or alpha-hydroxyketone
-may not happen if aryl group present at the end of the ketone because
dehydration happens more readily.
aldol condensation product Ans✓✓✓alpha, beta-unsaturated carbonyl
, piperonalpinacolone (mp 96 C)
4,4-dimethyl-1-(3,4-methylenedioxyphenyl)-1-penten-3-one.
aldol condensation (Acidic Conditions) Ans✓✓✓Oxygen of ketone or
aldehyde deprotonate acid e.g. H-Cl
aldol condensation enolate Ans✓✓✓resonance stabilized, negative
charge can be carried on either the carbon or oxygen
it is ambidentate; can do O-attack or C-attack.
sp3 hybridized C-H Ans✓✓✓pka 50
sp2 hybridized C-H Ans✓✓✓pka about 20
same as acetone
Mechanism of Base-Catalyzed Aldol Condensation Ans✓✓✓1. Base
abstracts alpha proton from the enolizable carbonyl giving the
nucleophilic enolate.
2. Electron rich carbon (nucleophile) attacks electron poor carbon on the
second aldehyde/ketone.
3.The remaining alpha proton is acidic enough to form conjugatively
stabilized alpha, beta- unsaturated carbonyl system that makes process
energetically favorable (Exo-, spontaneous)
