I've been taught that a carbocation mainly rearranges because of:
- increasing degree (1 to 2, 1 to 3, or 2 to 3)
- +M stabilization
- ring expansion (in an exceptional case, ring contraction as well).
However, I've never been taught whether the following carbocation A would rearrange:
My professor would say that this carbocation would not rearrange, since at the alpha position we only have two hydrogen atoms, and either of the hydride shifts would still yield a two degree carbocation B:
However I believe that B is stabilized by the strong inductive effect of three extra methyl groups (at the alpha position) that were absent in A. I believe this is a strong enough driving force for rearrangement.
So, can we say A will rearrange into B? Is there experimental evidence to support the fact that A rearranges/does not rearrange into B? Finally, based on these, can inductive effect be the sole driving force for carbocation rearrangement?