Chemical Forums
Chemistry Forums for Students => Organic Chemistry Forum => Topic started by: theufomusic on December 24, 2006, 04:41:12 PM
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Hello, Im just an Ex chemistry student (I completed second year, but didn't pass) and
im now wondering (just a thought experiment) if there is a way to completely cleave off
a carbonyl group and its carbonyl carbon; i.e Alpha cleavage (if I remember correctly.)
also, what would be a suitable reagent for performing this with an aromatic carbonyl?
Thankyou!
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You can sometimes decarbonylate aldehydes with Rhodium(I) catalysts. Ketones are much more difficult. You could consider Baeyer-Villiger oxidation followed by hydrolysis.
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You can sometimes decarbonylate aldehydes with Rhodium(I) catalysts. Ketones are much more difficult. You could consider Baeyer-Villiger oxidation followed by hydrolysis.
good idea.
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Thanks! that might work.
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You can sometimes decarbonylate aldehydes with Rhodium(I) catalysts. Ketones are much more difficult. You could consider Baeyer-Villiger oxidation followed by hydrolysis.
If you did a Baeyer-Villiger oxidation followed by hydrolysis on an aromatic ketone wouldn't you end up with the corresponding phenol? ... depending of course what was on the other side of the ketone - if the migratory ability of the other substituent was better than aryl you would end up with the arylcarboxylic acid which might decarboxylate. It's not really a decarbonylation though is it? Straight decarbononylation can be tough and it would depend on the specific example.
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Its tryptophan, actually ...
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You can sometimes decarbonylate aldehydes with Rhodium(I) catalysts. Ketones are much more difficult. You could consider Baeyer-Villiger oxidation followed by hydrolysis.
If you did a Baeyer-Villiger oxidation followed by hydrolysis on an aromatic ketone wouldn't you end up with the corresponding phenol? ... depending of course what was on the other side of the ketone - if the migratory ability of the other substituent was better than aryl you would end up with the arylcarboxylic acid which might decarboxylate. It's not really a decarbonylation though is it? Straight decarbononylation can be tough and it would depend on the specific example.
Yes, you're absolutely right. I was trying to come up with ways to cleave the C-C bond, which I think is the hardest part. You would end up with an alcohol, and your options for reducing an alcohol to an alkane are a lot better (TsCl then LAH, Barton-McCombie deoxygenation, etc.).