Sciencemadness Discussion Board

Iodination of dibenazlacetone

Bedlasky - 7-6-2023 at 10:53

Hi!

I tried to add some I2 on double bonds on dibenzalacetone. I dissolved 1,171 g of dibenzalacetone in DCM and 2,7 g of I2 also in DCM. I mixed both solutions, let them react for 20 minutes and then shake it with Na2S2O3 solution to remove all iodine. I separated DCM layer, dry it with anhydrous Na2SO4, filter it and let DCM evaporate. I obtained 0,94 g of orange, slightly wet solid with iodoform-like smell. Do anyone have idea what happened? This clearly didn't result in simple iodination (otherwise I would have 3,7 g of product).

clearly_not_atara - 8-6-2023 at 06:05

Iodine rarely adds efficiently to electron-deficient alkenes. Simple benzyl iodides are already reduced by HI (infamous hydriodic acid reduction of benzyl alcohols). But I2 might catalyze a cleavage of dibenzalacetone to cinnamic acid + styrene.

Pumukli - 23-6-2023 at 09:25

No info on iodination but brominations and chlorinations work like this:

Attachment: halodibenzalacetone.pdf (150kB)
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I don't know what you are planning with the iodo-compound (if anything) but maybe the bromo would be a viable alternative.