3
$\begingroup$

What are the orders of rates of oxidation with $\ce{HIO4}$ of the following diols? Explain with reasons.

(a) $\ce{Me2C(OH)C(OH)Me2}$
(b) $\ce{Me2C(OH)CH(OH)Me}$
(c) $\ce{CH2(OH)CH2(OH)}$
(d) $\ce{MeCH(OH)CH(OH)Me}$

I know that the reaction proceeds by forming a cyclic diester of periodic acid followed by cleavage of $\ce{C-C}$ bond and formation of $\ce{C=O}$ bond. But how do we compare the rates of the given compounds?

My first thought was to think $\ce{C-C}$ cleavage as formation of a pseudo carbocation which would be stabilised by +I effect of the alkyl groups and also the hyperconjugation, but I don't think it is right.

$\endgroup$
5
  • $\begingroup$ Could it possibly be related to stearic hinderance for the ring to form? $\endgroup$ Commented Mar 19, 2019 at 9:21
  • $\begingroup$ Could be but I am not sure $\endgroup$ Commented Mar 19, 2019 at 10:22
  • $\begingroup$ @SidharthGiri and Aditya One thing which you can be assured is that,whatever the differentiating factor is,it will certainly be before the formation of thr cyclic intermediate as after that,it is a pericyclic intramolecular rearrangement which is pretty easy to be done in all the cases with minimum requirement of any activation energy.. $\endgroup$ Commented Mar 19, 2019 at 10:39
  • $\begingroup$ Also.. Is the answer a>b>d>c? $\endgroup$ Commented Mar 19, 2019 at 11:10
  • $\begingroup$ I don't have the answers and that is also a big problem $\endgroup$ Commented Mar 19, 2019 at 13:04

0

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Browse other questions tagged or ask your own question.