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.

To determine which compound can be made from an aldehyde and CH3CO2CH3, let's analyze the options:

Option 1: CH3CO2CH2CH(OH)CH3

This compound appears to be a cyanohydrin, as it contains a hydroxyl group (-OH) attached to a carbon atom and a carbonyl group (C=O) adjacent to it. However, cyanohydrins are usually formed by generating CN- ions from HCN in the presence of a weak base, as stated in the question. In this option, there is no involvement of HCN or any weak base, so it is unlikely to be formed from an aldehyde and CH3CO2CH3.

Option 2: CH3CH2CH(OH)CH2CO2CH3

This compound does not contain a cyanohydrin functional group. Instead, it has a hydroxyl group (-OH) attached to a carbon atom adjacent to a carbonyl group (C=O). This arrangement corresponds to an aldol compound, which can be formed by generating -CH2CO2CH3 ions from CH3CO2CH3 using strong bases. Therefore, Option 2 is the correct answer.

In summary, Option 1 is incorrect because it does not involve the formation of a cyanohydrin, which is the expected product from the reaction of an aldehyde with CH3CO2CH3.