Answer :
Certainly! An aldol addition is a reaction between two molecules of an aldehyde or ketone with an α-hydrogen atom, typically catalyzed by a base or acid, resulting in the formation of a β-hydroxyaldehyde or β-hydroxyketone.
Since you want to see the aldol addition products for different compounds, let’s address them one by one.
### a. Butanal ([tex]$CH_3CH_2CH_2CHO$[/tex])
1. Reactants: 2 molecules of Butanal
- Structure: [tex]$CH_3CH_2CH_2CHO$[/tex]
2. Aldol Addition Product:
- First, we identify the α-hydrogen atoms in butanal. The α-hydrogen is on the carbon directly adjacent to the carbonyl group (aldehyde in this case).
- During the reaction, one molecule of butanal will act as the enolate ion (nucleophile) and the other as the electrophile.
3. Enolate Ion Formation:
- The α-hydrogen from one butanal molecule is removed to make the enolate ion: [tex]$CH_3CH_2CH=C(OH)H$[/tex]
4. Aldol Addition:
- The enolate ion then attacks the carbonyl carbon of another butanal molecule.
- This forms a new carbon-carbon bond creating a β-hydroxyaldehyde.
5. Final Product:
- The product will be 3-Hydroxy-2-ethylhexanal:
[tex]$CH_3CH_2CH_2CH(OH)CH_2CH_2CHO$[/tex]
### b. Acetone ([tex]$CH_3COCH_3$[/tex])
1. Reactants: 2 molecules of Acetone
- Structure: [tex]$CH_3COCH_3$[/tex]
2. Aldol Addition Product:
- Identify α-hydrogen atoms in acetone. The α-hydrogens are on either side of the ketone group.
3. Enolate Ion Formation:
- The α-hydrogen from one acetone molecule is removed to make the enolate ion: [tex]$CH_3C(O^-)=CH_2$[/tex]
4. Aldol Addition:
- The enolate ion then attacks the carbonyl carbon of another acetone molecule.
- This forms a new carbon-carbon bond creating a β-hydroxyketone.
5. Final Product:
- The product will be 4-Hydroxy-4-methyl-2-pentanone (commonly called Diacetone alcohol):
[tex]$CH_3C(OH)(CH_3)CH_2COCH_3$[/tex]
### c. Benzaldehyde ([tex]$C_6H_5CHO$[/tex])
1. Reactants: 2 molecules of Benzaldehyde
- Structure: [tex]$C_6H_5CHO$[/tex]
2. Consideration:
- Benzaldehyde has no α-hydrogen, so it does not undergo aldol addition.
### d. Cyclohexanone ([tex]$C_6H_{10}O$[/tex])
1. Reactants: 2 molecules of Cyclohexanone
- Structure: [tex]$C_6H_{10}O$[/tex]
2. Aldol Addition Product:
- Identify α-hydrogen atoms in cyclohexanone. The α-hydrogens are present on the carbons adjacent to the carbonyl group.
3. Enolate Ion Formation:
- The α-hydrogen from one cyclohexanone molecule is removed to make the enolate ion: [tex]$C_6H_9O^-$[/tex]
4. Aldol Addition:
- The enolate ion then attacks the carbonyl carbon of another cyclohexanone molecule.
- This forms a new carbon-carbon bond creating a β-hydroxyketone.
5. Final Product:
- The product will be 2-(Hydroxy(2-oxocyclohexyl)cyclohexanone: (often simplified as 3-Hydroxy-2-cyclohexen-1-one)
[tex]$C_6H_{10}C(OH)(C_6H_9)CO$[/tex]
These steps show the aldol addition products for the mentioned compounds a, b, and d, while c does not undergo such a reaction due to the lack of α-hydrogen.
Since you want to see the aldol addition products for different compounds, let’s address them one by one.
### a. Butanal ([tex]$CH_3CH_2CH_2CHO$[/tex])
1. Reactants: 2 molecules of Butanal
- Structure: [tex]$CH_3CH_2CH_2CHO$[/tex]
2. Aldol Addition Product:
- First, we identify the α-hydrogen atoms in butanal. The α-hydrogen is on the carbon directly adjacent to the carbonyl group (aldehyde in this case).
- During the reaction, one molecule of butanal will act as the enolate ion (nucleophile) and the other as the electrophile.
3. Enolate Ion Formation:
- The α-hydrogen from one butanal molecule is removed to make the enolate ion: [tex]$CH_3CH_2CH=C(OH)H$[/tex]
4. Aldol Addition:
- The enolate ion then attacks the carbonyl carbon of another butanal molecule.
- This forms a new carbon-carbon bond creating a β-hydroxyaldehyde.
5. Final Product:
- The product will be 3-Hydroxy-2-ethylhexanal:
[tex]$CH_3CH_2CH_2CH(OH)CH_2CH_2CHO$[/tex]
### b. Acetone ([tex]$CH_3COCH_3$[/tex])
1. Reactants: 2 molecules of Acetone
- Structure: [tex]$CH_3COCH_3$[/tex]
2. Aldol Addition Product:
- Identify α-hydrogen atoms in acetone. The α-hydrogens are on either side of the ketone group.
3. Enolate Ion Formation:
- The α-hydrogen from one acetone molecule is removed to make the enolate ion: [tex]$CH_3C(O^-)=CH_2$[/tex]
4. Aldol Addition:
- The enolate ion then attacks the carbonyl carbon of another acetone molecule.
- This forms a new carbon-carbon bond creating a β-hydroxyketone.
5. Final Product:
- The product will be 4-Hydroxy-4-methyl-2-pentanone (commonly called Diacetone alcohol):
[tex]$CH_3C(OH)(CH_3)CH_2COCH_3$[/tex]
### c. Benzaldehyde ([tex]$C_6H_5CHO$[/tex])
1. Reactants: 2 molecules of Benzaldehyde
- Structure: [tex]$C_6H_5CHO$[/tex]
2. Consideration:
- Benzaldehyde has no α-hydrogen, so it does not undergo aldol addition.
### d. Cyclohexanone ([tex]$C_6H_{10}O$[/tex])
1. Reactants: 2 molecules of Cyclohexanone
- Structure: [tex]$C_6H_{10}O$[/tex]
2. Aldol Addition Product:
- Identify α-hydrogen atoms in cyclohexanone. The α-hydrogens are present on the carbons adjacent to the carbonyl group.
3. Enolate Ion Formation:
- The α-hydrogen from one cyclohexanone molecule is removed to make the enolate ion: [tex]$C_6H_9O^-$[/tex]
4. Aldol Addition:
- The enolate ion then attacks the carbonyl carbon of another cyclohexanone molecule.
- This forms a new carbon-carbon bond creating a β-hydroxyketone.
5. Final Product:
- The product will be 2-(Hydroxy(2-oxocyclohexyl)cyclohexanone: (often simplified as 3-Hydroxy-2-cyclohexen-1-one)
[tex]$C_6H_{10}C(OH)(C_6H_9)CO$[/tex]
These steps show the aldol addition products for the mentioned compounds a, b, and d, while c does not undergo such a reaction due to the lack of α-hydrogen.
