0
$\begingroup$

Consider the case of pent-2-ene, what will happen if we make this compound undergo hydroboration oxidation?

I tried this by checking stability of partial positive charge developing on the carbon in the 4 membered cyclic transition state formed in the first step.

Since partial charges are formed, is it right to compare the stability based on Hyperconjugation?

Also, Is there any other,shorter method to predict the product?

|improve this question
$\endgroup$
  • $\begingroup$ For predicting regiochemistry look at the polarization of the double bond (tertiary>secondary>primary carbocation). Realize that boron is less electronegative (+) than hydrogen (-). Match up +/-. Markovnikov did not know about hydroboration. All of his examples had positive hydrogens. By matching polarities of the bonds of the reactants, hydroboration itself is a Markovnikov addition. Only after electropositive boron is replaced by electronegative oxygen does the two step reaction become anti-Markovnikov. $\endgroup$ – user55119 May 22 at 20:24