[beheada]

Basically I'm working on drawing up the mechanism for the addition of iodine monochloride to 1-methyl-1-cyclopentene.

My answer is that the double bond of the alkene attacks the iodine. I assume the reason for this is because the Iodine is "POLARIZABLE". My first assumption was that the double bond would attack the Chlorine in the first place, since Iodine's electronegativity makes it partially positive, and the negative normally goes after the positive. But since my professor said the yielded product was 1-chloro-2-iodo-1-methylcyclopentane, the double bond HAS to go after the iodine. The iodine forms a bridge on one side of the molecule when it is added, then the chlorine attacks the more substituted position and bears the correct product. So I assume that my answer is correct for going after the Iodine first, but I fail to understand WHY exactly it would happen that way.

Suggestions? Clarification?

[Dan]

My answer is that the double bond of the alkene attacks the iodine. I assume the reason for this is because the Iodine is "POLARIZABLE". My first assumption was that the double bond would attack the Chlorine in the first place, since Iodine's electronegativity makes it partially positive, and the negative normally goes after the positive.

The double bond is electron rich, so it will go for the somewhat electron deficient (delta +) iodine.

The iodine forms a bridge on one side of the molecule when it is added, then the chlorine attacks the more substituted position and bears the correct product.

Do you know why this is? Hint: do you think the chlorine attacks in an Sn1 or Sn2 fashion?

[beheada]

First off, thanks for pointing out that I already had the answer, just wasn't eyeballing it. Second off, the reason I have the chlorine attacking the more substituted group is because of Markovnikov's rule.
Our professor gave us a generalized rule stating the first group goes to the less substituted and the second goes to the more substituted. We went over the in-depth reasons for this, but is this what you mean?

[Dan]

Yeah, pretty much. I think Markovnikov's rule may be (technically) specifically for addition of HX species (I could be wrong), but it's the same principle anyway.