[tezha]

Under these particular conditions, which mechanism would take place? It is a secondary carbon so both are possible, the nucleophile is strong, which favors Sn2 reaction, however, the solvent is protic and the carbon is sterically hindered, which favours Sn1 reaction, is there gonna be an eqilibrium between these two mechanisms or is one going to prevail?

[Excelinthewall]

There's a problem, because you have got a ingombrant nucleophile and this take me to think is SN1. But in SN1, the Br- go out in te first step and whitin the help of any base. If you have a eccess of the solvent you have got a SN2, but i think you haven't. my first thought is there's a SN1 but, are you sure that's a SN? Because the nucleophile is good for elimination.
I'm so sorry for my bad english! 

[opsomath]

Nucleophile's too weak a base for elimination, especially in acid solvent.

This problem is kind of a dumb one; it's like an instructor sat down and thought "Hmm, what are all the ways people use to determine whether a reaction is SN1 or SN2" and then thought of an example that didn't fall into either. In my opinion, this reaction would probably give a mixture of the SN2 product and a bit of the rearranged SN1 product (nucleophile attaches to the tertiary carbon).

The closest thing I have ever done is a SN2 of a substituted benzoic acid with 1-bromooctane in DMF. It worked brilliantly, but these conditions are crappy compared to that. Really, this looks like a silly problem. If I wanted to make that acetate, I would start with the secondary alcohol and acetylate it with AcCl or Ac2O.

[tezha]

yeah im pretty sure it's SN, since the base is not as strong as OH- or alkoxide. the particular solvent, as far as i know, is more favourable for SN2 reactions since it is protic and h-bonds with anions.

[tezha]

Nucleophile's too weak a base for elimination, especially in acid solvent.

This problem is kind of a dumb one; it's like an instructor sat down and thought "Hmm, what are all the ways people use to determine whether a reaction is SN1 or SN2" and then thought of an example that didn't fall into either. In my opinion, this reaction would probably give a mixture of the SN2 product and a bit of the rearranged SN1 product (nucleophile attaches to the tertiary carbon).

The closest thing I have ever done is a SN2 of a substituted benzoic acid with 1-bromooctane in DMF. It worked brilliantly, but these conditions are crappy compared to that. Really, this looks like a silly problem. If I wanted to make that acetate, I would start with the secondary alcohol and acetylate it with AcCl or Ac2O.

Thanks man this makes sense. The book didn't ask me to tell what kind of mechanism it is so i shouldnt blame the authors, it was just me wondering what route does the reaction takes. yeah rearrangement seem reasonable too since you can get 1,2-shift there for a more stable carbocation.

[nox]

I second that this is a dumb question. In reality I'm positive that both S_N1 and S_N2 will occur to some extent.

[opsomath]

Sorry brother, didn't realize that the question was just you wanting more information rather than an instructor trying to be difficult. It's a good question, in my opinion the reaction as written would be kind of slow and suffer from the side product of rearrangement, but it would be primarily an SN2 reaction. Also there are better ways to get the same product. :p