Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Organic Chemistry Forum for Graduate Students and Professionals => Topic started by: Mitch on December 03, 2010, 02:05:21 AM
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I assume the following mechanism occurs for the reaction of PCL-1 with hydrogen peroxide. The H2O2 decomposes to radicals which removed the B(OH)2 forming B(OH)3. But, I just don't know how or why the product is a ketone or how luciferin got separated from PCL-1. Any help would be appreciated.
Figure is from http://dx.doi.org/10.1073/pnas.1012864107
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So the oxidation steps of the typical anitmarkovnikov Brown hydroboration/oxidation goes as shown in attached image A. Peroxide anion (not HO radical) attacks boron. Alkyl migration (with loss of HO-), followed by basic hydrolysis gives the antimarkovnikov alcohol.
So by analogy, here's what I think might (might) be happening in vivo (attached image B). Same attack of HOO-, alkyl migration, and hydrolysis gives a deprotonated phenol derivative. The alkoxide anions collapse to form the C=O double bond, and kick out the O- on the opposite side of the ring.
Can't promise it's correct, but I can push the arrows to make it work. :)
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Thank you, you saved my hide. I was presenting this paper at journal club today and I just has a sense he would ask for the mechanism, because of you I was able to bust it out seamlessly. Thanks again.
Have you had a chance to read the paper at all? I'm just curious if you had any overall thoughts about it?
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Glad to help. This seems like a clever way to measure peroxide levels. Their comment about intra- versus intercellular H2O2 is an interesting one, though. I don't know enough about the biology side to comment on the merits of the research, but chemically I like the use of the aryl boronic acid as a peroxide-labile protecting group.