The major product formed in the following reaction is

Concept:

→ The reaction you described is a bromination reaction, where 3-methylthiophene is reacted with N-bromosuccinimide (NBS) in the presence of a radical initiator such as (PhCOO)₂ and benzene (C₆H₆) under heat.

→ The reaction mechanism involves the formation of a bromine radical from NBS, which reacts with the 3-methylthiophene molecule to form a thiophene radical intermediate.

→ This radical intermediate then reacts with molecular bromine to form a more stable intermediate. This intermediate then undergoes rearrangement to form 3-(bromomethyl)thiophene as the major product.

Explanation:

The reaction can be summarized as follows:

→Step 1: Formation of a bromine radical from NBS:

NBS + heat → Br• + NsH

→ Step 2: Reaction of the bromine radical with 3-methylthiophene to form a thiophene radical intermediate:

Br• + 3-methylthiophene → 3-methylthiophene radical

→ Step 3: Reaction of the thiophene radical intermediate with molecular bromine to form a more stable intermediate:

3-methylthiophene radical + Br₂ →

→ Step 4: Rearrangement of the intermediate to form 3-(bromomethyl)thiophene as the major product:

→ 

Conclusion: Therefore, the major product formed in the reaction of 3-methylthiophene in the presence of NBS, (PhCOO)₂, C₆H₆, heat is 3-(bromomethyl)thiophene. Therefore, the correct answer is option 1 .