Orgo question. please help!

[JDHK]

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http://datbootcamp.com/wp-content/uploads/2013/02/Q3Question1.jpg

I got this problem correctly just because the answer choices didn't have what I really wanted to put, but why doesn't this want to do SN1 reaction? Br is a good leaving group from a tertiary carbon, which would make a stable carbocation. It's also in a protic solvent. It is actually e2 mechanism. How do I know?

 

[Jokrino]

http://datbootcamp.com/wp-content/uploads/2013/02/Q3Question1.jpg

I got this problem correctly just because the answer choices didn't have what I really wanted to put, but why doesn't this want to do SN1 reaction? Br is a good leaving group from a tertiary carbon, which would make a stable carbocation. It's also in a protic solvent. It is actually e2 mechanism. How do I know?

NaOCH3 is strong base, hence E2.

 

[ayel91]

-OCH3 is a strong nucleophile and a strong base, which prefers E2/Sn2. The leaving group is on a tertiary carbon, so E2, it's got a Hydrogen it can abstract once the single bond rotates to a antiperiplanar beta position.

You look at the Base/Nucleophile first, then the Electrophile, and then solvent I think...

 

[sakthivs]

The primary reason why you dont do sn2 here is because remember sn2 cant even perform backside attack on tertiary carbons. Therefore, E2 is the only option here.

 

[biomolecmed]

When a reagent is a strong base, you do elimination, unless you are dealing with primary halide. In that case do sn2.

 

[calvzzz]

Every here answered it perfectly, however, I highly recommend that you watch Chad's videos if you are still struggling with ochem.

 

[JDHK]

Thanks everyone!! I was watching Chad's videos and taking notes, but looks like I got a bit ahead of myself. After I continued to watch, it's much clearer and is in my head now =)