2
$\begingroup$

Would one get 1-(1-chloroethyl)-1-methylcyclobutane?

I am not sure if the driving force identification is correct? Is my going from a 2° to a 3° carbocation correct? Does anyone have any tips for knowing when to look out for rearrangements?

$\endgroup$
3
$\begingroup$

I think the solvolysis would involve rearrangement to the cyclopentyl carbocation as indicated in the figure below. The driving force for the rearrangement is two-fold

  1. without rearrangement, the cyclobutyl compound would generate a secondary carbocation; with rearrangement a more stable tertiary carbocation is generated instead
  2. release of strain as the 4-membered ring opens to a 5-membered ring

enter image description here

The tertiary cyclopentyl carbocation ultimately captures a solvent molecule as indicated.

$\endgroup$
  • $\begingroup$ the + charge goes onto the cyclic ring. Does that destabilize the ring more than having a 4-membered ring? $\endgroup$ – yolo123 Nov 1 '14 at 20:45
  • $\begingroup$ An $\ce{sp^2}$ carbon would like to be around 120 degrees; that angle is not destabilizing in 5-membered or larger rings. $\endgroup$ – ron Nov 1 '14 at 20:53

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.