Quantcast

Ring Expansions

This forum made possible through the generous support of SDN members, donors, and sponsors. Thank you.

hsjordan24

Full Member
2+ Year Member
Joined
May 24, 2017
Messages
56
Reaction score
55
Ring Expansions seem to be giving me a little bit of trouble. I have watched both Chad's and Mike's and only Mike covers it (for 2 seconds) so I assume its not a high yield topic but better safe than sorry. Based on my understanding, it's an SN1 mechanism and occurs to relieve ring strain. I would assume it would mostly likely show up on the DAT in a 3 or 4 membered ring but I could be mistaken. I'm not sure how to identify when it will occur on a given problem. Any help would be appreciated

Thanks!
 

orgoman22

DAT DESTROYER
Lifetime Donor
Sponsor
Vendor
15+ Year Member
  • Joined
    Mar 12, 2005
    Messages
    4,595
    Reaction score
    3,367
    Ring Expansions seem to be giving me a little bit of trouble. I have watched both Chad's and Mike's and only Mike covers it (for 2 seconds) so I assume its not a high yield topic but better safe than sorry. Based on my understanding, it's an SN1 mechanism and occurs to relieve ring strain. I would assume it would mostly likely show up on the DAT in a 3 or 4 membered ring but I could be mistaken. I'm not sure how to identify when it will occur on a given problem. Any help would be appreciated

    Thanks!
    Usually...if you have a ring expansion, expect to see a 3 or 4 membered ring with an exocyclic double bond.Often something like HBr or HCl are added. Many other examples do exist however. Refer to an organic text that will easily show you 3 or 4 worked out examples. McMurray and Klein have several.

    Hope this helps.

    Dr. Romano



    ring sdn.png
     
    • Like
    Reactions: 1 user

    hsjordan24

    Full Member
    2+ Year Member
    Joined
    May 24, 2017
    Messages
    56
    Reaction score
    55
    Usually...if you have a ring expansion, expect to see a 3 or 4 membered ring with an exocyclic double bond.Often something like HBr or HCl are added. Many other examples do exist however. Refer to an organic text that will easily show you 3 or 4 worked out examples. McMurray and Klein have several.

    Hope this helps.

    Dr. Romano



    View attachment 222167
    That makes much more sense now thank you very much.
     
    • Like
    Reactions: 1 user
    Top