NitreRat
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Defluorodation(?) of substituted fuorobenzenes to benzenes.
I recently managed to cheaply obtain a liter of fluorobenzene. I bought it with the intention of converting it into benzene, which is hard to obtain
where I live. Unfortunately the Ph - F bond is one of the strongest in organic chemistry. You can't just substitute the fluoro group for a hydride
ion. Even hydrogenation with Pd catalyst won't work.
The two methods I have been able to find that can reduce aromatic fluoro groups include:
1. The use of various transition-metal based ligands to form complexes with the aromatic rings, thus activating the ring and making the fluorine more
susceptible to nucleophilic substitution.
2. A combination of CeCl3, LiAlH4 in THF can reduce the halogen substituant via a radical mechanism.
While both of these methods might be useful in a fine-chemical synthesis, I would be doing it on a 1L scale so the reagents involved are far beyond my
budget for such a simple task.
Does anyone have any experience reducing aromatic fluoro groups? Can it be done on a larger scale with a simple metal reduction such as sodium,
potassium or activated zinc powder?
Thanks,
NitreRat
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CuReUS
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Raney Ni in the presence of NaOH can remove F from benzene ring.
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Nicodem
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Thread Moved
8-5-2016 at 01:29 |
NitreRat
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At room temp and atmospheric pressure?
Couldn't that also hydrogenate the ring as well, or is that only significant at higher temperatures and/or pressures?
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CuReUS
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yes,see this
http://oeh.tandfonline.com/doi/abs/10.1080/15298669191364686
and this
http://link.springer.com/article/10.1007/s00706-010-0362-9#p...
| Quote: | | Couldn't that also hydrogenate the ring as well, or is that only significant at higher temperatures and/or pressures? |
the ring would get hydrogenated at 100'C under pressure
[Edited on 9-5-2016 by CuReUS]
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