s_col
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Epoxidation Question
Hey all,
I'm just beg ginning my journey with chemistry and am a little stuck.
Currently i am going over epoxidations an extremely useful reaction in organic chemistry. If your substrate is an aromatic with other functional
groups (carboxylic acid , aldehyde, ester) does this effect epoxidations ? Are these groups oxidized in addition to the epoxidation of the alkene ?
s_col
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Metacelsus
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It depends on the oxidant used. mCPBA, which is the standard reagent for epoxidations, in general tolerates other functional groups well, but will
also oxidize aldehydes. Esters and carboxylic acids will not react.
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s_col
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thank you for the prompt reply cheddite cheese
mCPBA is a little out of my reach but microscale percarboxylic and dioxirane epoxidations are feasible for me. Will for peracetic acid oxidize
aldehydes and epoxidate the double bond ? into a epoxy carboxylic acid ?
s_col
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zed
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Maybe. Aldehydes are quite vulnerable to oxidation. Oxidations are hard to stop, once they get rolling. Given a strong oxidizing agent, and
acetic conditon, you could end up with benzoic acid, after starting out with cinnamaldehyde.
What are you actually attempting to do?
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zed
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Whoops! Sorry. I can no longer edit my original post.
That epoxy acid might decarboxylate to form an aldehyde which would then be oxidized to an acid, Etc. There is a synthetic strategy wherein this
sequence is artfully utilized.
An intermediate epoxy-ester is fairly stable, and upon hydrolysis, away from oxidizing agents, may yield an aldehyde of one less carbon atom.
Glycidic esters, may be formed via the the Darzen's Glycidic Ester condensation. But, alternately, oxidation of an unsaturated ester should work.
https://en.wikipedia.org/wiki/Darzens_reaction
[Edited on 29-9-2015 by zed]
[Edited on 29-9-2015 by zed]
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