No Nucleophiles in E1 Reactions?

[johnwandering]

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I can't believe I didn't notice until now...

So:

1.) SN2
polar aprotic solvent
Decently strong nucleophile
Low temperature
NOT Acidic/Basic

2.) SN2
Polar protic solvent
weak nucleophile
Low Temperature
NOT Acidic/Basic

3.) E2
Nonpolar nonprotic solvent (examples?)
Very Strong Nucleophile
High Temperature
Basic Conditions

4.) E1
Polar Protic Solvent
No Nucleophile
High Temperature
Acidic Conditions



I was wondering if these were correct (especially the E1). E1 just seems to be SN1 but no nucleophile, higher T, and more acidic.
Also, I assumed a polar protic solvent because the condition is supposed to be acidic?

 

[rjosh33]

I can't believe I didn't notice until now...

So:

1.) SN2
polar aprotic solvent
Decently strong nucleophile
Low temperature
NOT Acidic/Basic

2.) SN2
Polar protic solvent
weak nucleophile
Low Temperature
NOT Acidic/Basic

3.) E2
Nonpolar nonprotic solvent (examples?)
Very Strong Nucleophile
High Temperature
Basic Conditions

4.) E1
Polar Protic Solvent
No Nucleophile
High Temperature
Acidic Conditions



I was wondering if these were correct (especially the E1). E1 just seems to be SN1 but no nucleophile, higher T, and more acidic.
Also, I assumed a polar protic solvent because the condition is supposed to be acidic?

Yeah these look about right (though I think you meant SN1 for #2).

As far as E1 is concerned, higher temps always favor the elimination reactions. From what I recall, E1 really doesn't take place too often, and is usually just a (minor) competing reaction with SN1. About the only time I recall a significant amount of E1 occurring was when a secondary or tertiary alcohol is treated with sulfuric acid. The bisulfate byproduct is a terrible nucleophile, and the protonated alcohol ends up undergoing an E1 reaction (HSO4- steals a proton, thus regenerating the catalyst) to form an alkene.

And the polar protic solvent is preferred to help stabilize the carbocation intermediate.

 

[sparkles21]

This is unrelated...but do we have to know elimination reactions or any reactions involving alkenes, since they are not on the list of topics for ochem?