zephler1
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Expected yield from LiAlH4 reduction of nitropropene to alkyl amine?
Some references suggest at best, one can expect a 65% yield (using 5 equivalents of LiAlH4); does anyone have any real world experience with yields
from this reaction?
There is a document on Rhodium "Large scale MDA from piperonal" in which the authors use just a 2x excess of LiAlH4, explicitly state that they do not
reflux the mixture being reduced and that they get a 77% yield. This statement is highly suspect as not one published paper comes close to that
yield, and bear mind that these papers all use a 5x stoichiometreic ratio of LiAlH4 and they reflux - I have a hard time believing that the key to
higher yields and better atom economy is the lack of refluxing - any comments?
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Bert
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Thread Moved
8-10-2014 at 06:35 |
Templar
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oops, this looks a bit too obviously drug related to be on here!
LAH reductions are not very fun. LAH is dangerous blah blah flammable ethers blah blah
Just run it with Al/Hg and see what you get. Workups can get complex quickly with LAH. I have reduced novel phenyl propyl nitroalkenes using aluminum
turnings in good consistent yield of roughly 50%, just run with that.
If you're dealing with nitrostyrenes, its best to use Zn/acid reduction, borohydride and then Zn reduction, or borohydride then Pd/C CTH reduction.
LAH if you have plenty of it and THF to use as the solvent because ether SUCKS
He who fights with monsters should be careful lest he thereby become a monster. And if thou gaze long into an abyss, the abyss will also gaze into
thee.
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