Q7P-b - Organic Chemistry (Mcmurry)

Question

What products would you expect from reaction of the following alkenes with NBS? If more than one product is formed, show the structures of all.

Step-by-Step Solution

Answer

Step 1: Bromination of allylic alkenes

In this reaction, the two product formed are not in equal proportions. The reaction at the two ends is not equal because of the formation of a unsymmetrical allylic radical. Thus, the reaction at the primary end (which is less hindered) is favoured.

Step 2: Bromination of 2-methylhex-3-ene

Bromination of 2-methylhex-3-ene with NBS results in the formation of four different bromohexenes and two different allylic radicals.

The reaction is given below:

                          Product formation between given alkene and NBS