## nincompoop one year ago sooooooo simple

1. nincompoop

2. nincompoop

|dw:1436681727482:dw|

3. nincompoop

if you do not agree, please provide a justification

4. Photon336

Ok so in that first step the hydrogen is added to the more substituted side, leaving the positive charge on the carbon that gives a 2* carbocation. So we have secondary carbocation that's stabilized by resonance, but why doesn't it re-arrange, VIA hydride shift to get the 3* carbocation. I understand the whole resonance stabilization .. I thought the order was 3>2 (resonance)>2>1>methyl

5. taramgrant0543664

I was thinking the same sort of thing as @Photon336

6. Photon336

@taramgrant0543664 Yeah.. this must be an exception

7. Photon336

If oxygen donates electrons to that carbon in one of those resonance structures, then it's less electropositive ..

8. taramgrant0543664

Ya it could be everything makes sense in a way but I was definitely questioning that

9. Photon336

then again I guess that could explain why the H SHIFT doesn't happen maybe because of the fact that electrons that were shifted in the second resonance structure.

10. Photon336

I forgot the whole resonance structure rules order, it's something like minimize charges, satisfy octet. etc .. etc..

11. nincompoop

carbon rearrangement is a possibility and I did not use that because the clue is in the product :) the end product showed a less-substituted therefore I must provide an explanation why that took place with the given information I have.

12. nincompoop

you can have mixture of products where there's rearrangement that occurred in addition to what the problem provided us

13. nincompoop

14. Empty

Although cute and it works out, I don't know if "resonance stabilization" is the correct reasoning because "resonance" is sort of the naive view of frontier molecular orbital theory. But whatever, I just thought it'd be fun to sorta look at this problem more in depth since I need to maintain my ochem knowledge! See, the oxygen is actually more of an $$sp^2$$ hybridization in this scenario, so if we draw out a diagram of the molecular orbitals with lowest energy at the bottom to higher energy at the top we have: |dw:1436711052622:dw| So in the bottom one we see that all the p-orbitals are conjugated together to form one large molecular orbital, which corresponds to our lowest energy state. The next row up we have introduced a single node, this is making an antibonding orbital here between the tertiary carbon and the secondary carbon while keeping the $$\pi$$ bond between the secondary carbon and the oxygen. This higher energy state is where the bond forms between the hydrogen and tertiary carbon. A quick aside in case you're wondering why didn't I draw this asymmetry the other way around? Well that would correspond to this reaction: |dw:1436711439753:dw| Ok obviously we're not gonna react through this route lolol. I didn't bother drawing this molecular orbital up there because we're really just comparing the two possible reactions, so let's compare the other one at the very top which corresponds to putting a hydrogen smack dab in the middle of our quantum mechanically stable molecular orbital giving us 2 nodes, really drastically destabilizing our molecular orbital! Nature, like me, is super lazy so it'll just take the easiest route. You could probably show that this reaction happens the other way too by heating the reaction, it would be a fun reaction to test to see if we actually do get the other product. That's the thing with chemistry though, the theory is more or less a nice guide line. Also when I saw this problem on a completely unrelated note I thought it was funny if we could end up with an epoxide out of this with an alternative minor minor minor minor product: |dw:1436711910975:dw| lololol ok just playing around for funsies. :P

15. Empty

If you're not familiar with the whole molecular orbitals being used like this thing, I think you'd enjoy reading these and looking specifically at these 3 reactions here: https://en.wikipedia.org/wiki/Woodward%E2%80%93Hoffmann_rules#Original_formulation That's sorta the standard intro to disrotatory and conrotatory electrocyclic reactions and how heat or light is what determines the shape based on symmetries of the molecular orbitals. Woodward was an amazing guy, and probably the most easy to read chemistry papers I've ever seen despite him describing how his lab has synthesized some of the most astounding things such as chlorophyll!!

16. nincompoop

|dw:1436718201665:dw|

17. nincompoop

LOL

18. nincompoop

|dw:1436718355477:dw|

19. Empty

Nothin' like a "resonance structure" with a +2 charge on oxygen lol XD

20. nincompoop

some of the portions of the drawing is cut off from my end so I can't really figure out if you drew more

21. Empty

Nah I didn't I don't think. I was just messing around anyways

22. abb0t

I've never thought to use newman projection to "check".

23. Jaynator495

o-o