[physstudent1]

HCl is added to 2-methyl-2-butanol at room temperature. To the product of this reaction is added sodium ethoxide in ethanol. To the product of this second reaction is added HBr in the presence of peroxides.  this is a homework question of mine.  I understand what happens when HCl is added to the alcohol in the first step. ( The Cl replaces the alcohol)  I think that after that an ether is formed?  But I am confused on what role peroxides and HBr will play after that  can anyone offer some help? 

[macman104]

Try again for the ether.  How do you propose you form the ether?  You cannot do SN2, remember it's a 3° carbon.  Instead, what else happens, if you have a base (your ethoxide) and a halogen with a proton nearbye?  Now what role can HBr with peroxides do to that compound?

[physstudent1]

does elimination occur because a carbocation is formed?

[macman104]

Yup, or possibly E2.

[physstudent1]

so an alkene will form b will HBr and the peroxide btake the alkene and make a primary alcohol?

[macman104]

Good!

[physstudent1]

I'm a little confused on which carbon the OH will go to to and where and if the BR will go at all we didn't cover the reaction of alkenes really I just looked a few chapters ahead in the book.

[physstudent1]

what I have before the peroxide and HBr are added is an alkene with 4 carbons and a methyl on the 2nd carbon the double bond placed between the 2nd and third carbon  from here I'm kind of confused

[nextpauling]

I don't think the function of the peroxide is to add a hydroxyl group...I would say it acts as a radical initiator...so you have an alkene, HBr, and a radical initiator...the thing to remember about alkenes is that they have an easily broken pi bond...as a hint I will tell you that the peroxide acts as a facilitator for the reaction between the alkene and HBr...

[macman104]

http://www.chemguide.co.uk/mechanisms/freerad/alkenehbr.html

[physstudent1]

alright thanks a lot really helpful