Question

In the given reaction

 ‘A’ can be

• A. Benzyl bromide.
• B. Bromo benzene
• C. Cyclohexyl bromide
• D. Methyl bromide

Answer 1

The Correct Option is A

To determine the correct compound 'A' in the given reaction, we will analyze the reaction steps and products:

1. The reaction shows the transformation of a compound 'A' using the reagents given in three steps:
   • (i) 2\, \text{Mg, THF}: This step indicates the formation of a Grignard reagent. Grignard reagents are typically formed by reacting alkyl or aryl halides with magnesium.
   • (ii) \text{Methyl benzoate}: This step suggests a nucleophilic attack by the Grignard reagent formed in the first step.
   • (iii) \text{H}_2\text{O/H}^+: This is a hydrolysis step that usually produces an alcohol.
2. Considering the final product shown:
   • The structure is a tertiary alcohol with three aromatic rings, which corresponds to a triphenylmethanol structure.
   • This suggests the addition of a phenyl Grignard reagent to a carbonyl group.

Analyzing the given options:

1. Benzyl bromide: This compound can form the phenyl Grignard reagent needed for the reaction to form the triphenylmethanol.
2. Bromo benzene: Though it can also form a Grignard reagent, it would react differently, more suited for simple phenyl additions.
3. Cyclohexyl bromide: This would result in a cyclohexyl Grignard, which is not suitable for forming the final aromatic alcohol.
4. Methyl bromide: Would yield a methyl Grignard reagent, leading to a different alcohol product.

Based on the above analysis, the compound 'A' most likely is Benzyl bromide. It correctly fits the description of reagents and leads to the formation of the anticipated triphenylmethanol product.