2
$\begingroup$

I am trying to figure out the product for the following reaction: enter image description here

Its a Prins Reaction. My proposed mechanism for it is:

enter image description here

In my second step, that particular carbocation is formed since $\ce{Ph}$ is an electron-withdrawing group.

Mechanism looks neat enough, but the reaction given in Wiley's Solomon and Fryhle (Page 379) is:

enter image description here

I'd like to know why my mechanism is "wrong"? I think there's problem in the carbocation generation step but isn't the carbocation that I have formed more stable?

$\endgroup$
  • 1
    $\begingroup$ The carbocation will definitely form at the benzyl carbon. The fact that the benzene ring can stabilize the cation through resonance outweighs the disadvantages of negative inductive effect. $\endgroup$ – Pritt says Reinstate Monica Mar 30 '18 at 11:51
2
$\begingroup$

Your generation of electrophile is correct the subsequent primary carbocation formation by the attack of electrophile is incorrect.

In my second step, that particular carbocation is formed since $\ce{Ph}$ is an electron-withdrawing group.

The benzene ring stabilizes the carbocation through mesomeric effect.

The electrophile will attack at $\alpha$ position rather than $\beta$

enter image description here

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.