Mike
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Hydrogenation of esters
Hi!
Like you know NaBH4 doesn’t hydrogenate esters to alcohols.
What’s my problem? I want to reduce esters (aliphatic and aromatic) to alcohols without using LiAlH4.
Will NaBH4 at least reduce the ester to a aldehyde and alcohol? Like when we use DIBAH? Then the aldehyde can be turn to alcohol by reacting with
NaBH4 and H3O(-).
I heard about activating NaBH4 by adding NiCl2. Apparently using this method the –CN group is quickly reduce to –NH2. Normally NaBH4 doesn’t
reduce –CN. I wonder if it works for the esters.
Maybe someone has more certain information about hydrogenation of esters without LiAlH4?
best regards,
Mike
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guaguanco
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| Quote: | Originally posted by Mike
Will NaBH4 at least reduce the ester to a aldehyde and alcohol? Like when we use DIBAH? Then the aldehyde can be turn to alcohol by reacting with
NaBH4 and H3O(-).
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I don't think so; Esters are stable little suckers.
A google search revealed some catalytic techniques that are out of reach of the home chemist. An old-school route would be:
ester -> acid -> acid chloride -> aldehyde -> alcohol, but I know you're looking for something easier.
What ester are you trying to reduce?
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Mike
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Actually I want to: benzoic acide =>methyl benzoate=>benzyl alkohol
Any ideas?
To make an acid chloride I will need SOCl2 wich I can't get.  The only hope is
in that NaBH4/NiCl2 way.
best regards,
Mike
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guaguanco
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Then again, some esters can be reduced with NaBH4
http://www.albmolecular.com/features/tekreps/vol07/no51/
Everything you wanted to know about NaBH4
http://www.rohmhaas.com/hydride/pdf/finaldigest.pdf
It appears that under the right conditions, BH4- is a much stronger reducing agent that has been traditionally thought!
[Edited on 20-1-2004 by guaguanco]
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Mike
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Thanx a lot! This is just what I was looking for.
best regards,
Mike
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