E2 always favor less sub while E1 favor most sub?

[atlanta213]

E2 always favor less sub while E1 favor most sub?

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[happyana]

both reactions favor tertiary, secondary, and then primary.

 

[klutzy1987]

E2 always favor less sub while E1 favor most sub?

E2 reactions will favor the more sunbstitutedwhen using a small unhindered base like sodiummethoxide. Hoewever when using a large sterically hindered base like t-butoxide, E2 favors the less substituted. E2 also favors the less substituted by a hoffman elimination reaction, and by enamine formation.

I cant think of any E1 reaction that favor the less substituted right now, but i am sure that there are a couple.

 

[Electrons]

Is ethoxide or propoxide consider as strong and bulky or strong and non-bulky?

 

[klutzy1987]

No the only big'n'bulky that you will see is t-butoxide.

 

[Electrons]

Ok so the methoxide, ethoxide, proxide, n-butoxide are all considered strong but non-bulky right?

No the only big'n'bulky that you will see is t-butoxide.

 

[klutzy1987]

Ok so the methoxide, ethoxide, proxide, n-butoxide are all considered strong but non-bulky right?

WTH is peroxide doing in this group??

Also i do not know about n-butoxide, but i have never seen that used anywhere.

 

[PreDent2009]

First off, E1 and E2 are two completely different reactions that run by different mechanisms. E2 is a strong base reacting with a leaving group, leaving you with the most stable alkene system. E1 runs through a carbocation intermediate and will always favor the most stable alkene system as well, since the carbocation will shift, if possible, to the most stable carbon. E1 only happens when reacting an alcohol with a very strong acid such as H2SO4, or H3PO4. That is the only situation.

E2 always favor less sub while E1 favor most sub?

 

[Electrons]

WTH is peroxide doing in this group??

Also i do not know about n-butoxide, but i have never seen that used anywhere.

lol, woops, I meant n-propoxide and n-butoxide which is CH3CH2CH2O-Li and CH3CH2CH2CH2O-Li respectively.

 

[atlanta213]

In summary, E1 is zaitesiv ( heat and strong acid(H2SO4, H3PO4<--strong acid??)) E2 zaitesiv and hoffman elimination ( most zaitesiv, but hoffman occurs when (strong bulky base present) right??

 

[PreDent2009]

Yes, H3PO4 is an extremely strong acid. Think about it. The conjugate base H2PO4 is an extremely weak base because the charge can be delocalized around a numberous atoms, more so that HSO4-. Hoffman elimination occurs when you have an amine on your molecule and you react it with 1. excess CH3-I, followed by 2. Ag20. These are the hoffman reagents and you get the least substituted product.

In summary, E1 is zaitesiv ( heat and strong acid(H2SO4, H3PO4<--strong acid??)) E2 zaitesiv and hoffman elimination ( most zaitesiv, but hoffman occurs when (strong bulky base present) right??