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Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: electronuc on March 12, 2018, 04:29:38 PM

Title: Is a higher substituted alkoxide more or less stable than eg. methyl oxide?
Post by: electronuc on March 12, 2018, 04:29:38 PM

So i can't figure this out.
There aren't any resonance forms to stabilize one more over another. Which is a better leaving group? (I know that alkoxides are strong bases - poor leaving groups)
Can it be that the higher substituded alkoxides are less stable because there are more electrons that destabilizes the negatively charged anion?

Title: Re: Is a higher substituted alkoxide more or less stable than eg. methyl oxide?
Post by: electronuc on March 13, 2018, 06:48:52 AM

I mean methoxide and not methyl oxide, was tired when I wrote the first post.. -_-

Title: Re: Is a higher substituted alkoxide more or less stable than eg. methyl oxide?
Post by: Babcock_Hall on March 13, 2018, 09:02:57 AM

I am not sure what you are asking.  You might compare the pK_a values of methanol, ethanol, and tert-butanol, as a starting point.

Title: Re: Is a higher substituted alkoxide more or less stable than eg. methyl oxide?
Post by: electronuc on March 14, 2018, 05:27:01 AM

Quote from: Babcock_Hall on March 13, 2018, 09:02:57 AM

I am not sure what you are asking.  You might compare the pK_a values of methanol, ethanol, and tert-butanol, as a starting point.

Thanks! What I've learned now is that methanol is more acidic in solution than an alcohol with more branching due to solvation.
So, methoxide would theoretically be a better leaving group than a bigger alkoxide as it will be more stable in a solution.

I was trying to rank how fast a reaction would be for the same compound but with different alkoxides as leaving groups.
I first assumed that an electric effect played a part in the stabilty of ionic compounds.