[sheemee]

Hi I am a student in my first year studying organic chemistry.  Today our professor asked us whether or not degenerate hydride shifts exist and if we could design an experiment to prove it.  I only slightly understand hydride shifts (not into great detail, but I know what it is) however I do not understand what a degenerate hydride shift is or how to go about creating an experiment to prove it.  If anyone could briefly explain it to me and explain whether or not it exists that would be of great.  Also if you know how or are able to come up with a way to prove it experimentally that would also really help a lot.

Thanks,
Sheemee

[Squirmy]

A degenerate hydride shift would mean the carbocation after rearrangement is the same as the one before rearrangement.

It may be interpreted more generally that both carbocations have the same degree of substitution...both tertiary for example.

[James Newby]

from wiki

http://en.wikipedia.org/wiki/Hydride_shift

This is the example i know of.  Have you used any techniques to prove a mechanism yet?

[Squirmy]

I didn't consider sigmatropic rearrangements, but that makes sense with the question...can certainly have identical/degenerate structures in starting material and product in that type of reaction.

Didn't think anyone studied those reactions in their 1st year of organic. Then again, I'm sure none of my first year students would have a clue what I meant if I used "degenerate" in that context.