In my class test, I was asked this question:

Which mechanism would be followed by a certain reaction with good leaving group?

  1. E1 reaction

  2. E2 reaction

  3. No reaction

  4. both E1 and E2

I answered 4 because they both occur simultaneously the main difference comes in the amount of product formed by them. But, I was awarded with negative marks.

Can anyone please tell if I was wrong on my part or my teacher?

  • $\begingroup$ One point is: Your comparison of E1, E2 and E1cb should equally consider if there is synchronicity (e.g., the approach of a base and leaving of an other group across a transition state) or one after the other (passing intermediates, e.g. a base deprotonates the substrate, the carbanion then expels an other group) to yield e.g., an alkene. Which is not the same as letting $\ce{X-}$ leave to generate an intermediate carbocation eventually loosing H to yield an uncharged alkene. $\endgroup$
    – Buttonwood
    Dec 13 '20 at 15:05
  • $\begingroup$ the reaction can follow any pathway just the conitions make one case or the other more probable $\endgroup$
    – user99515
    Dec 13 '20 at 17:34
  • $\begingroup$ Yes there are reactions which possibly could proceed by more than one pathway, already because on occasion it may be easier to reject a suggested mechanism than to collect supporting experimental evidence. Thus the suggest that you add to your question the reaction in question, to set it in specific context to your question. $\endgroup$
    – Buttonwood
    Dec 13 '20 at 18:44
  • $\begingroup$ Take note also of the temperature at which the reaction is allowed to move— E1 reactions usually perform under high temeperatures (based from my Org Chem class in first year). $\endgroup$
    – Ellie
    Dec 14 '20 at 10:53
  • 1
    $\begingroup$ IMO this question is nonsensical because you can't generally make a strong statement on ideas in organic chemistry. There are no hard and fast rules. $\endgroup$
    – 666User666
    Dec 15 '20 at 3:53

Your Answer

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