Question

The final product A, formed in the following multistep reaction sequence is:

• A.

  

• B.

  

• C.

  

• D.

  

Answer 1

The Correct Option is A

Step 1: The reaction starts with the bromobenzene reacting with Mg in ether to form the Grignard reagent (phenylmagnesium bromide).

Step 2: Carbon dioxide is then introduced, which reacts with the Grignard reagent to form benzoic acid upon acidic workup.

Step 3: The benzoic acid undergoes a Hoffmann bromamide reaction, where the amide is converted to an amine, resulting in the formation of aniline.

Thus, the final product formed is aniline (structure in option (1)).

Answer 2

Let's analyze the given multistep reaction sequence to determine the final product A.

The reaction sequence involves the following steps:

1. Step 1: The bromobenzene is treated with \(\text{Mg, ether}\)to form a Grignard reagent. This step involves the conversion of the bromine atom to a magnesium bromide group.
2. Step 2: The Grignard reagent is then reacted with \(\text{CO}_2\)followed by acid workup \(( \text{H}^+ )\). This results in the formation of benzoic acid.
3. Step 3: The benzoic acid is further treated with \(\text{NH}_3, \Delta\)(heat), which can form an amide (in some cases, this method may lead to a rearranged product depending on the specifics of the reaction conditions).
4. Step 4: The amide is then subjected to the Hofmann bromamide reaction using \(\text{Br}_2, \text{NaOH}\). This reaction typically results in the loss of the carboxylic acid group and formation of an amine with one less carbon atom than the original acid.

Given these steps, the product A will be aniline (phenylamine), as the Hoffmann bromamide degradation converts the benzamide to a primary amine.

The correct structure is depicted in the image labeled as Option 1.