Question

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

• 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 $C–2$

During charge rearrangement the species that migrates is decided by the migratory aptitude which is as follows:
Migratory aptitude: $H^{-}>P{h}^{-}>3^{0}Carbanion>2^{0}Carbanion>1^{0}Carbanion>{}^{-}C{H}_3$
Now in this question, the `'H'` on C-2 carbon will migrate because of formation of a more stable (due to resonance) ${}^{+}C-O$ carbocation.