[Sveinjk]

Hello I am having a project in an organic synthesis course were im making 3-borpinacolpyrrol from pyrrol, I think I have most of the mechanism figured out but I would appreciate if somebody could take a look and see if im on the right track or if im completely lost . Is my reaction to simplified...
The project is two steps were im in the first do remove an H wit t-BuLi on the pyrrol and put on a TIPS group (-Si(iPr)₃)so that when I use diboris-pinacolat it will substitute in 3-posision instead of in 2-position. This is going to be used later in an suzuki cross coupling reaction.

I think that the mechanism is proceeding like this:
The free elctrons on nitrogen will go into the ring and the double binding in the ring will connect with half of the pin₂b₂ and give the product 3-borpinacolpyrrol(see picture 2).
Does anybody have any idea in what way the iridium catalysator is helping the reaction.
Im putting along two pictures, the first showing the reaction while the last shows how I think the reaction proceeds. Any help would be appreciated.
If anybody is interrested in the original litterature that is:
Tetrahedron Letters 43 (2002) 5649-5651. Iridium-catalysed

[img=http://img503.imageshack.us/img503/4756/bildefq6.th.png]
[img=http://img147.imageshack.us/img147/9806/bilde2oq9.th.png]

[alphahydroxy]

Does anybody have any idea in what way the iridium catalysator is helping the reaction.
 
If anybody is interrested in the original litterature that is:
Tetrahedron Letters 43 (2002) 5649-5651. Iridium-catalysed

Well, I have just had a very brief glance at the paper which you have cited, and it talks about the mechanism in the last couple of paragraphs... It's often useful to read the article before asking questions about the chemistry...

They talk of tris(boryl)iridium (III) complexes as intermediates, which then prmote C-H activation and subsequent C-B bond formation. I reckon a steric argument explains the regioselectivity of the reaction in question too.