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A reaction I am trying to perform says to use a strong base like Sodium Amide with Acetone and Iodo-Benzene as reactants with DMSO as the solvent to form Phenylacetone. The main idea is to use the Acetone Enolate to form Phenylacetone when the Halogen is removed from the Halobenzene.

Can I just put NaOH in Acetone with a Halobenezene?

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  • $\begingroup$ you are far more likely to form mesityl oxide with those conditions $\endgroup$ – Waylander Mar 30 at 18:07
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I could be wrong but I think this reaction works by forming benzyne, which then undergoes enolate attack:

enter image description here

I don't think hydroxide is basic enough to do this, so no I don't believe your proposed reaction conditions will work. Is there any reason you can't just use NaNH2, or BuLi, LDA etc.?

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  • $\begingroup$ BuLi will probably do lithium-halogen exchange, but I agree hydroxide doesn't work $\endgroup$ – orthocresol Mar 30 at 20:56
  • $\begingroup$ Thank you for the suggestion. I had NaOH readily available, and wondering if that would work just as well. NM2 will take longer to get a hold of. $\endgroup$ – Steven Cakeman Mar 31 at 3:26
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I'm almost certain that this reaction will not proceed for both reasons outlined above. NaOH is also not soluble in acetone. Additionally NaOH is not basic enough to deprotonate acetone to form the lithium enolate so even if you could do SnAr, you would just end up catalysing the formation of mesityl oxide. The enolate must be formed all at once to stop this happening. So in short, no you cant just do as you suggest.

I've never seen this done via benzyne (although I haven't looked) but there are rather a lot of palladium catalysed reactions of this type in the lit. Also some cool procedures from acetylacetone using Cu(I) (C-C acitvation!).

Hope this helps x

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