Question

In the following carbocation, which $H/C{H}_3$ is most likely to migrate to the positively charged carbon?

• A. $C{H}_3$ at $C-4$
• B. $H$ at $C-4$
• C. $C{H}_3$ at $C-2$
• D. $H$ at $C-2$

Answer 1

The correct option is D $H$ at $C-2$

Generally carbocation will undergo rearrangement to form a more stable carbocation than before.
The given carbocation is secondary and methyl migration in this compound will give secondary carbocation. Thus, it does not gives any extra stability to the carbocation so this rearrangement is not favourable.
H-shift from $C-4$ gives a stable tertiary carbocation.
But H-shift from $C-2$ gives the most stable carbocation because it involves in resonance stabilisation with the alcohol group at $C-2$