1. Dismiss Notice
  2. Guest, be sure to check out How To Get Into Dental School, our free downloadable PDF with step-by-step details for dental school applicants!
    Dismiss Notice
  3. Dismiss Notice
  4. Download free Tapatalk for iPhone or Tapatalk for Android for your phone and follow the SDN forums with push notifications.
    Dismiss Notice

Sn1, E1, Sn2, E2

Discussion in 'DAT Discussions' started by Dencology, May 29, 2008.

  1. Dencology

    2+ Year Member

    Joined:
    Mar 7, 2008
    Messages:
    396
    Likes Received:
    0
    Status:
    Pre-Dental
    guys i am going crazy over this stuff. anyone out there has a good way of explaining when to go either way. i know the general basic for sn1, sn2, ... but i still get some questions wrong which i should nailed them. any help?
     
  2. Note: SDN Members do not see this ad.

  3. userah

    7+ Year Member

    Joined:
    Aug 9, 2007
    Messages:
    555
    Likes Received:
    0
    Status:
    Dental Student
    I'll break it down

    Sn1
    - 3*>2*>1*
    - Prefer polar protic solvents (water,methanol, etc)
    - Only dependent on the LG (not the nucleophile)
    - Formation of carbocation intermediate
    - Because it forms carbocation intermediate, Nu can attack from top or bottom, so you get racemic mixtures (thus you have optical inactivity)
    - Achiral intermediate

    E1
    - Pretty much same as everything stated for Sn1
    - Hard to really differentiate between E1 products and Sn1 products although kaplan says E1 preferred at higher temperatures

    Sn2
    - 1*>2*>3*
    - Prefer polar aprotic solvents (DMSO, etc) (lack acidic hydrogens)
    - Bimolecular, so dependent on LG and Nu
    - Inversion of products because of backside attack by Nu (basically it switches config. S becomes R or R becomes S)
    - Product is optically active
    - Best Nu are basic atoms

    E2
    - Easier to differentiate between Sn2 and E2
    - E2 is not sterically hindered like Sn2 so it can attack tertiary carbons as long as you have a STRONG BASE
    - So if you see a strong base and a tertiary alkyl halide think E2.

    that's all i can think of for now. maybe if you tell me what kind of problems you're having trouble with, i can be of more help.
     

Share This Page