Formation of Substitution Product from 1-Bromo-2,6-Dimethylcyclohexane

[chiyakotiten]

Only a substitution product is obtained when the compound below is treated with sodium methoxide. Draw the substitution product and explain why an elimination product is not obtained

(If the image doesn't show up, the compound is 1-bromo-2,6-dimethylcyclohexane)

Homework Equations

- The compound is a secondary structure
- It is going to be an SN2 reaction(?)

The Attempt at a Solution

Is it because sodium methoxide is a weak base, but a good nucleophile which favors SN2 reactions?

 

[zorro]

Sodium methoxide is a strong base which favours SN2.
Your product for SN2 is wrong. The nucleophile attacks from the rear end of the leaving group.
Regarding elimination -
Hint: What is the requirement for elimination? Is the hydrogen easily available for abstraction? Does it require high energy transition state?

 

[zorro]

Edit: Sodium methoxide is not a strong base...just stable.

 

[Yanick]

Sodium Methoxide is stable because its a salt, as soon as you have a polar solvent involved you get sodium cation plus a methoxide anion. Alkoxides are fairly strong bases. pKa of alcohols are ~15.5-16.

To the OP. For a hint at why elimination won't happen, draw the most stable chair conformer of the reactant and you will see the answer.

And as far as the products of your substitution reaction go, remember what happens to stereochemistry as you go through SN1 or SN2 mechanisms.