Question

6. Which of the four carbocations shown is the most stable (will not rearrange) and which one(s) will undergo carbocation rearrangement(s)? Indicate the correct structures of the products of the carbocation rearrangements. To practice for the exam: use resonance structures to explain why you selected specific a carbocation as the most stable. Where applicable, use the curved arrow(s) to clearly draw the mechanism of the carbocation rearrangement. HO HO A. carbocation B is most stable and will not rearrange, and the products of rearrangements are LOHY HO X from A from from D B. carbocation B is most stable and will not rearrange, and the products of rearrangements are HO Он from A from from D is most stable and will not rearrange, and the products of C. carbocation A rearrangements are HO OH from B from C from D D. carbocation A is most stable and will not rearrange, and the products of rearrangements are HO OH from B from c from D E. carbocation B is most stable and will not rearrange, and the products of rearrangements are OH from A from C from D

Answer 1

Carbocation bearing hydroxyl group is most stable because the carbocation is it is in conjugation with hydroxyl group. Hence, carbocation B) is most stable and will not undergo any rearrangement.

Carbocation A undergoes rearrangement of C-C sigma 1,2-shift.

Carbocation C undergoes 1,2-methyl shift to give carbocation bearing hydroxyl group.

Carbocation D undergoes 1,2-hydride shift to give benzylic carbocation.

Thus answer is option B).