[nonlinear]

In Sn1 reactions, the stability of the carbocation is very important. Is the "magnitude" of carbocation stabilization offered from resonance usually greater than the difference between secondary and tertiary? I know of course the stabilization that phenol offers will be much greater than anything else generally, but what if it were something like a Nitrogen, or an oxygen? Would that resonance stabilization still be significant, and more importantly, would it stabilize the carbocation more than an additional R group would?

Thank you!

[orgstudy]

I know that stabilization by a simple 3 degree is more than in allylic or benzyl carbocation (also benzly carbocation is more stable than allylic)

[Schrödinger]

@orgstudy : I don't think that is correct. Benzylic is more stable than the simple tertiary carbocations.
Please correct me if I am wrong

[voidSetup]

Ya I think resonance stabilizes a carbocation better than it being tertiary.  For example, look at this mechanism for the protection of an alcohol as a THP ether.  It's a secondary carbon but it is stabilized by the adjacent oxygen via resonance.

http://www.organic-chemistry.org/protectivegroups/hydroxyl/thp-ethers.htm

[nox]

Ya I think resonance stabilizes a carbocation better than it being tertiary.  For example, look at this mechanism for the protection of an alcohol as a THP ether.  It's a secondary carbon but it is stabilized by the adjacent oxygen via resonance.

http://www.organic-chemistry.org/protectivegroups/hydroxyl/thp-ethers.htm

That's resonance from a heteroatom, which is completely different than resonance from a phenyl ring because with the heteroatom, you can still have full octets on each atom whereas this can't happen with a phenyl ring.

Also according to my textbook a primary benzylic carbocation is about as stable as a secondary carbocation. So yes a tertiary > primary benzylic.

[adianadiadi]

benzyl group is more stable than tertiary

[nox]

^that really depends on how many benzyl groups you have

of course a tertiary benzylic carbocation will be extremely stable, but a primary benzylic carbocation is only about as stable as a secondary carbocation

[orgstudy]

@orgstudy : I don't think that is correct. Benzylic is more stable than the simple tertiary carbocations.
Please correct me if I am wrong

i also think that resonance is more effective than 3 degree ... but i read it at some page of wiki ... so i assumed i'm wrong

PS: i tried but i cant find that page again ... :p

[orgstudy]

^that really depends on how many benzyl groups you have

of course a tertiary benzylic carbocation will be extremely stable, but a primary benzylic carbocation is only about as stable as a secondary carbocation

that must be because of hyperconjugation