Cyanohydrins can be made from carbonyl compounds by generating CN- ions from HCN in the presence of a weak base.
In a similar reaction, -CH2CO2CH3 ions are generated from CH3CO2CH3 by strong bases.
Which compound can be made from an Aldehyde and CH3CO2CH3?
Option 1 : CH3CO2CH2CH(OH)CH3
Option 2 : CH3CH2CH(OH)CH2CO2CH3
The correct answer is Option 2. I understand why. But I do not understand why Option 1 is incorrect. Please help/advise me.
Option 1, CH3CO2CH2CH(OH)CH3, cannot be formed from an aldehyde and CH3CO2CH3.
In the reaction to form a cyanohydrin, the CN- ion from HCN adds to the carbonyl carbon of the aldehyde, forming a new carbon-carbon bond. This results in the formation of a cyanohydrin, where the OH group and the CN group are attached to the same carbon atom.
However, in Option 1, there is no CN group present. Instead, there is an OH group and an ethyl group attached to the same carbon atom. This is not formed through the addition of a CN- ion, so it is not a cyanohydrin.
On the other hand, Option 2, CH3CH2CH(OH)CH2CO2CH3, is formed from an aldehyde and CH3CO2CH3 in the presence of a strong base. In this reaction, the -CH2CO2CH3 ion generated from CH3CO2CH3 attacks the carbonyl carbon of the aldehyde, forming a new carbon-carbon bond. This reaction is similar to the formation of a cyanohydrin but with a different attacking group. Therefore, Option 2 is the correct answer.
To determine which compound can be made from an aldehyde and CH3CO2CH3, we can start by looking at the reaction conditions and the reagents involved.
In the given information, it is stated that CH3CO2CH3 reacts with strong bases to generate -CH2CO2CH3 ions. This suggests that CH3CO2CH3 functions as a nucleophile in the reaction.
Now, let's consider Option 1: CH3CO2CH2CH(OH)CH3. To obtain this compound, we would need an aldehyde (RCHO) and CH3CO2CH3. The question asks whether this is possible.
To form a cyanohydrin, we typically expose a carbonyl compound (aldehyde or ketone) to HCN and a weak base, which generates CN- ions. The CN- ions then react with the carbonyl compound to form a cyanohydrin. This reaction is known as the cyanohydrin synthesis.
However, in Option 1, we are given CH3CO2CH3 instead of HCN as the reagent. Since CH3CO2CH3 is a weak base, it cannot generate CN- ions. Therefore, we cannot use Option 1 to obtain CH3CO2CH2CH(OH)CH3 from an aldehyde and CH3CO2CH3.
Next, let's consider Option 2: CH3CH2CH(OH)CH2CO2CH3. To obtain this compound, we would need an aldehyde (RCHO) and CH3CO2CH3. Can we use this combination?
As we discussed earlier, CH3CO2CH3 acts as a nucleophile when reacted with strong bases. In this case, we have CH3CO2CH3 reacting with a strong base to generate -CH2CO2CH3 ions. These -CH2CO2CH3 ions can act as a nucleophile and attack the carbonyl carbon of an aldehyde to form a nucleophilic addition product.
Therefore, Option 2, CH3CH2CH(OH)CH2CO2CH3, is the correct answer. It represents the nucleophilic addition product formed when CH3CO2CH3 reacts with an aldehyde (RCHO).
In summary, Option 1 does not represent a compound that can be obtained from an aldehyde and CH3CO2CH3 due to the reaction conditions and reagents involved.