From: Uno Maeorg (uno$##$chem.ut.ee)
Date: Sat Sep 07 2002 - 16:15:11 EDT
Hi colleague,
If your bromide is active enough you can use the activated zinc-copper
reagent according to the http://www.ch.ic.ac.uk/ectoc/papers/14/ which is
much simples to prepare that Riecke zink.
By the way, by the reaction of your starting alcohol with HBr water
solution also some part of ester group could be hydrolyzed. Therefore
it is better to use a milder procedure i.e. Ph3PBr2 or even better to
prepare mesylate or tosylate. Both of them you can later reduce in mild
conditions.
Good luck.
Dr. U. Maeorg
On Mon, 2 Sep 2002, JSM wrote:
> I wish to Dehydroxylate an organic compound.The
> conventional methods used to do this are rather harsh,
> detrimental to other functional groups in the
> molecule,
> involve expensive reagents and difficult conditions.
> I have theoretically come up with a possible method.
> I want the following : R-OH -> R-H
> This is how I have proposed the method / steps :
> R-OH + HBr(48% sol) -> R-Br + H2O ....1
> R-Br + Zn (powder) -> R-ZnBr ....2
> R-ZnBr + H2O(Dil acid)->R-H + ZnBrOH..3
> (Note: R contains an ester group)
> Compare to GRIGNARD reaction :
> R-MgI + H2O -> R-H + MgI(OH).
> The above is used to destroy excess Grignard reagent.
> It cannot be used in reactions where there is an ESTER
> group,as the R-MgI will react with it.
> Please tell me if my Steps 1-3 above are feasible,and
> any precautions, drawbacks associated with it.Thanks,
> My e-mail : jaininder2002$##$yahoo.com
>
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-- Uno Maeorg ! e-mail : uno$##$chem.ut.ee University of Tartu, Institute of Organic Chemistry! phone : +(3727)375243 2 Jakobi St, Tartu 50090, Estonia ! fax : +(3727)375243_______________________________________________ ORGLIST - Organic Chemistry Mailing List Website / Archive / FAQ: http://www.orglist.net To post a message (TO EVERYBODY) send to everybody$##$orglist.net To unsubscribe, send to everybody-request$##$orglist.net the message: unsubscribe your_orglist_password your_address List coordinator: Joao Aires de Sousa (coordinator$##$orglist.net)
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