Acidity

[florida21]

On question number 212 in the 2015 Destroyer, it says that ethers won't react with grinards since it doesn't have an acidic H. However, can't the carbon adjacent to the oxygen lose a hydrogen and be resonance stabilized with the oxygen making it acidic?

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[zEkii]

Diethyl ether is too stabilized by both the carbons occupying the oxygen molecule in the ether. Therefore it is unreactive(happy). But if it was an ester, that might be a different story.

 

[Dental_14]

I remember that Grignard's Reagent is usually used with ether as the solvent, since it's aprotic. I think that since ether is non-acidic it therefore won't react with Grignard's (base)

 

[BYU4you]

None of the protons on an ether are acidic.
And no carbonyl means it won't react.

 

[whitepapertree]

None of the protons on an ether are acidic.
And no carbonyl means it won't react.

I believe he is wondering about the reasoning for the protons not being acidic rather than just they're not. I think he's looking at the two lone pairs on the oxygen and wondering why there wouldn't be a double bond formed via deprotonation of neighboring carbon.

 

[florida21]

^ yes that is what I am trying to say. Higher acidity means more stability and the resonance with the Oxygen should add stability

 

[BYU4you]

The C-H bond strength is just to great to give up the Hydrogen.

 

[DAT Destroyer]

On question number 212 in the 2015 Destroyer, it says that ethers won't react with grinards since it doesn't have an acidic H. However, can't the carbon adjacent to the oxygen lose a hydrogen and be resonance stabilized with the oxygen making it acidic?

Ethers have nothing to stabilize the anion !!!!!! Ethers are not acidic at all. Esters with alpha protons are somewhat acidic.....pKa around 25. We exploit this in reactions such as the Claisen Condensation. Thankfully,,,,,ethers are not acidic,,,,,we run reactions like Grignards in them,,,,,and they make excellent solvents. Hope this Helps

Dr. Romano

 

[florida21]

is this not allowed to happen? The oxygen would be allowed to have the negative charge.

 

[joiedevivre86]

is this not allowed to happen? The oxygen would be allowed to have the negative charge.View attachment 193184

An ether would be considered a base really, because it has electrons to donate (the lone pairs on the O). But disregarding that fact, go back to that piece of paper you attached above and draw in the lone pairs on the O. The structure is unreasonable (extremely unstable) because you have two lone pairs on the O as well as a double bond, and the octet rule is violated. There's not really resonance here anyway - there's no other spot for those extra electrons to go - they're not going to sit on the C and form a carbanion, because carbon is not very electronegative compared to oxygen.

 

[florida21]

Thank you!