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My instructor pointed out that furfural undergoes haloform reaction - I don't understand how. I couldn't figure out the mechanism on my own, and couldn't find much online either. (regarding the products, or the mechanism) Could someone please help me out?

As far as I know, only methyl ketones and alcohols oxidisable to the same undergo haloform reaction - so something unexpected must be happening here.

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It'd be great if you could provide a detailed mechanism and explanation, and if possible provide sources.

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  • $\begingroup$ Are you sure it was "furfural undergoes haloform reaction" or was it maybe "furfural undergoes reaction with haloforms"? The latter happens in methanolic KOH to give methoxy-(2-furyl)-acetic acid. $\endgroup$ – Zhe Aug 2 '18 at 17:07
  • $\begingroup$ I think it's the latter, the reaction of furfural with haloforms in alkaline medium. Could you highlight the mechanism? $\endgroup$ – arya_stark Aug 2 '18 at 17:30
  • $\begingroup$ pubs.acs.org/doi/abs/10.1021/ja01500a061?journalCode=jacsat I don't have time to draw it out, but hopefully you can just figure it out from this. $\endgroup$ – Zhe Aug 2 '18 at 17:44
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    $\begingroup$ @Mithoron I don't understand what you are saying. To my knowledge there's no misunderstanding on anyone's part. Maybe mishearing... $\endgroup$ – Zhe Aug 2 '18 at 19:52
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    $\begingroup$ @Zhe Your paper is about synthesis and your earlier comments suggests misunderstanding on OP's part. I say furfural does react in environment used for haloform reaction, just in different way. $\endgroup$ – Mithoron Aug 2 '18 at 20:56
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Aldehydes can be oxidized by bromine under acidic conditions per the mechanism is given below. The haloform reaction, however, occurs under basic conditions and requires a methyl ketone. Your professor probably forgot that the haloform is for methyl ketones in basic conditions and called the reaction below a haloform even though it isn't. Given the similarity in the oxidation of the carbonyl group to a carboxylate with a halogen, (and the thousands of organic reactions to remember,) it seems like a simple easy mistake.

oxidation of aldehyde with bromine

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