March 19, 2024, 12:09:59 AM
Forum Rules: Read This Before Posting


Topic: Reaction of HCl with 3-methylcyclopentene  (Read 7987 times)

0 Members and 1 Guest are viewing this topic.

Offline malonicman

  • New Member
  • **
  • Posts: 4
  • Mole Snacks: +0/-0
Reaction of HCl with 3-methylcyclopentene
« on: September 30, 2010, 10:36:36 PM »
Yesterday, I came across a problem involving the reaction of HCl with 3-methylcyclopentene to yield 3-bromo-3-methylcyclopentene.  It requests a reasonable mechanism for said reaction.  I'm at quite a loss, as I am only familiar with the mechanism for the reaction yielding 3-bromo-3-methylcyclopentane by electrophilic addition with a hydride shift.  Any hints or suggestions?

Thanks

Offline ooosh

  • Regular Member
  • ***
  • Posts: 85
  • Mole Snacks: +3/-3
Re: Reaction of HCl with 3-methylcyclopentene
« Reply #1 on: September 30, 2010, 11:43:08 PM »
I don't know how can you get bromide by using hydrogen chloride.

Offline malonicman

  • New Member
  • **
  • Posts: 4
  • Mole Snacks: +0/-0
Re: Reaction of HCl with 3-methylcyclopentene
« Reply #2 on: October 01, 2010, 12:36:06 AM »
Yesterday, I came across a problem involving the reaction of HCl with 3-methylcyclopentene to yield 3-chloro-3-methylcyclopentene.  It requests a reasonable mechanism for said reaction.  I'm at quite a loss, as I am only familiar with the mechanism for the reaction yielding 3-chloro-3-methylcyclopentane by electrophilic addition with a hydride shift.  Any hints or suggestions?

Thanks
I meant to write "chloro."

Offline plankk

  • Full Member
  • ****
  • Posts: 150
  • Mole Snacks: +20/-4
  • Gender: Female
Re: Reaction of HCl with 3-methylcyclopentene
« Reply #3 on: October 01, 2010, 12:53:52 AM »
If we talk about chlorine derivatives, the NCS should do everything what you want (look for Wohl-Ziegler Reaction, it is exactly a reaction with NBS but NCS should work exactly in the same way).

Offline Doc Oc

  • Chemist
  • Full Member
  • *
  • Posts: 564
  • Mole Snacks: +48/-12
Re: Reaction of HCl with 3-methylcyclopentene
« Reply #4 on: October 01, 2010, 01:07:29 AM »
If that's all the information you're given then it sounds like a typo.  Check w/the prof.

Offline orgopete

  • Chemist
  • Sr. Member
  • *
  • Posts: 2636
  • Mole Snacks: +213/-71
    • Curved Arrow Press
Re: Reaction of HCl with 3-methylcyclopentene
« Reply #5 on: October 01, 2010, 10:04:57 AM »
That looks like a pretty generic example of an electrophilic addition of HCl (protonation of the double bond), rearrangement to the more stable carbocation, and addition of chloride to the more stable carbocation. It isn't a chlorination reaction.
Author of a multi-tiered example based workbook for learning organic chemistry mechanisms.

Offline malonicman

  • New Member
  • **
  • Posts: 4
  • Mole Snacks: +0/-0
Re: Reaction of HCl with 3-methylcyclopentene
« Reply #6 on: October 01, 2010, 08:46:58 PM »
I checked with grad students who had worked on the same problem set last year, and indeed it is an error.  I was driving myself mad over nothing!!!

Thanks.

Sponsored Links