OC question from datqvault

[steppingstone]

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from datqvualt:
2-methyl-1-cyclohexene with HI/THF...
- because THF is aprotic...wouldn't this go through SN2 and not SN1?? Would there be a 'proton shift' (datqvault is saying it will have a proton shift)

 

[ekephant]

To be honest I dont remember studying this reaction (HX/THF). But if I were to guess, I don't think this is a substitution reaction, it looks more like an addition... since there is no leaving group, and there is an alkene.

 

[IsaacYankem]

I've never seen HI/THF solution before, but this definitely can't go SN1/SN2,due to the SP2 hybdrid carbons in the alkene and thus has to be an addition. sp3 carbons do SN1/SN2

I think this an addition reaction. The double bond attacks H-I, adding H first to the formerly double bonded carbon, the other C now has a + charge and can indeed shift to the more substituted position where Iodine will then be the second atom added.

 

[biomolecmed]

There must be a mistake on this problem.You cannot have 2-methylcyclohexene. It should be named 1-methylxyclohexene and HI will do a Marmovnikov's addition by adding an Iodine to the tertiary carbon to make 1-methyl,1-iodocyclohexane. Hope this helps. Good luck.

 

[steppingstone]

If someone can tell me how to upload an image onto this forum, I can attach the problem to this! It is actually 3-methyl-1-cyclohexene. Sorry, I didn't realize I had put a 2 instead of a 3.

My question now is: in addition reactions, methyl/proton shifts are possible like they are in SN1?