Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: Rutherford on February 23, 2014, 05:21:44 AM
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The problem is attached, I need to determine the unknown compounds. I will attach my attempt in the next post.
The whole problem can be found here http://icho2014.hus.edu.vn/Preparatory-Problems/0001/01/Preparatory-Problems-224.html it is the 23rd.
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What transformation will F undergo?
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What happens to the primary radical you formed by closing the ring. Is there not a substituent on that methyl group?
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What substituent?
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Do the radical cyclisation you end up with a primary radical, what happens to it?
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I forgot the radical on the methyl group, it will undergo a transformation with the azide, right? But where does the methyl on nitrogen come from?
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I don't think it reacts with the azide
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What else path could afford the final compound?
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If your compound F is correct, what could compound G be?, Compound G looses N2 after acid treatment. So F must be some sort of reactive intermediate that transforms to G, your F will not do anything.
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OK, you have a primary radical, lets say it reacts with the azide, what compound do you get?
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this compound
the thing the smiles had marked C(1) is supposed to be a radical
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The primary radical has to react with nitrogen, N2 will be released, so the final compound after treatment with CH3X would be obtained, I think. But I can't think of a mechanism for the reaction.
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No, do it stepwise:
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Then the lone pair from nitrogen will end up forming a triple bond, and the other N-N bond will be cleaved to form nitrogen molecule and a radical that will abstract a hydrogen to obtain I?
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more or less:
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One nitrogen in the nitrogen molecule would have 2- charge.
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you got the structure, you figure out the charges pls
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In the path you wrote. the nitrogen doesn't lose it's negative charge, so in the formed nitrogen molecule one nitrogen would be negative.
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Then in the drawing I forgot to change it.
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I didn't know this right off, so I had to do some searching for some of the steps. I suggest you write out every single step. Then it might be helpful to draw the alternate form of the azide. I think the cyclization step may look different and the radical mediator mechanism will change. I don't think there is any Me3SiH forming.
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Thanks orgopete,
How do you see this proceeding?. There is a Google books reference to domino reactions, this is in there.
sorry for the long link
http://books.google.ch/books?id=HfdEud1Qvq0C&pg=PA229&lpg=PA229&dq=horsfiline+synthesis&source=bl&ots=7PPPMvUUwd&sig=VRI_o85y_Wm4GbOC1bXi5JE-p6c&hl=en&sa=X&ei=EtsJU-2mIOL_ygO33oHACw&ved=0CFwQ6AEwCjgK#v=onepage&q=horsfiline%20synthesis&f=false (http://books.google.ch/books?id=HfdEud1Qvq0C&pg=PA229&lpg=PA229&dq=horsfiline+synthesis&source=bl&ots=7PPPMvUUwd&sig=VRI_o85y_Wm4GbOC1bXi5JE-p6c&hl=en&sa=X&ei=EtsJU-2mIOL_ygO33oHACw&ved=0CFwQ6AEwCjgK#v=onepage&q=horsfiline%20synthesis&f=false)
I invoked the R3SiH to provide a source of the H radical after (during) the nitrogen elimination. So you end up with a radical initiator for the next reaction.
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I got this:
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That's OK, but where does the H radical come from?
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They gave above the reaction arrow: +H+ and -N2, although I think that it is a mistake and that it should be radical hydrogen.
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I think it comes from the silane.
Let's see if orgopete has a different source.
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In the scheme, it was written as "+H+". Since the literature was using TTMSS, it showed a TMS on the nitrogen. This propagated the radical for cleaving the iodine and initiating the reaction. So I presume protonation was to cleave the silyl group. I didn't see any other hydrogen source. If a tin hydride were used, that would be different.