• Advice You're Thankful for Contest

    Now that it's getting close to Thanksgiving, we're running a contest to hear advice you've received that you're most thankful for! This can be any type of advice and the advice with the most reactions will win!

    JOIN CONTEST

Ochem RoadMap 3 Question

NuckingFutz

Full Member
10+ Year Member
7+ Year Member
Nov 20, 2006
140
0
  1. Dental Student
    I've been studying the Destroyer roadmaps all day and I have most of it down :D

    However, there is a couple things that are confusing me on the 3rd Road Map (probably due to brain fatigue).

    From the starting point, going either left or right yields in the binding of Br to the most substituted carbon. However, at the very top to the left, we see the Br from the HBr acid binding to the LEAST substituted carbon. I'm probably missing something simple but I can't really think of the reason why at the moment...

    At first I thought that because Br- is a weak base, it would be an E1 mechanism and thus bind to the most substituted carbon, but this isn't the case with the reaction having the HBr reagent.

    Thanks :p
     

    DRHOYA

    Full Member
    10+ Year Member
    May 15, 2008
    746
    1
    NY
    1. Pre-Dental
      Very good question. The way I like to think of it is this. At the starting compound in the center, you react that with Br2 under hv. In this rxn, the Br will add to make the most stable, which here would be adding to the C with the CH3 group attached which is a tertiary carbon. In the rxn at the top of the page, the difference arises in 2 aspects. 1.) There is no longer a CH3 group attached to the cyclopentane, but a =CH2. 2.) The rxn this time is HBr/ROOR. In this rxn, b/c of the double bond and rxn conditions, the Br adds to the least substituted carbon in an elimination rxn. This is why you get CH2Br. Hope that helps.
       
      About the Ads
      This thread is more than 13 years old.

      Your message may be considered spam for the following reasons:

      1. Your new thread title is very short, and likely is unhelpful.
      2. Your reply is very short and likely does not add anything to the thread.
      3. Your reply is very long and likely does not add anything to the thread.
      4. It is very likely that it does not need any further discussion and thus bumping it serves no purpose.
      5. Your message is mostly quotes or spoilers.
      6. Your reply has occurred very quickly after a previous reply and likely does not add anything to the thread.
      7. This thread is locked.