Re: ORGLIST:Grignard reaction

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From: peter walla (peter.walla$##$post.sk)
Date: Sun Oct 26 2003 - 06:25:50 EST


Dear Dr Omar Faruk Khan!

I have some experiences with organometallic reagents, maybe it will help you.
At first i would like to tell you, you have assured all the requisite pre-conditions for handling and working with air and water sensitive substances, so you dont need to be worried, that the reaction failed because of it.
Regarding the nucleophilic properties of organolithium compounds, i have read somewhere that these are not the best reagents of choice for reactions with esthers or nitriles, but unforunately i can not find the reference.
In your place I would certainly conduct the reaction via grignard reagent (4-quinolinyl-magnesium bromide, which i would prepare from 4-bromoquinoline and magnesium in ether by sonication at RT, not exceeding the concentration 0.5 M) which are much more effective in this type of reactions.
The reaction of formed Grignard reagent with nitriles (i dont know how is it with esthers) is very!!! solvent dependent, please check:

http://www.rhodium.ws/chemistry/grignardnitrile.html

Or

JACS 1948,70,426.

Hope it will help you!
Best reagrds!

Peter

> Dear All
>
> I am trying to synthesize ketones from
> 4-halyl-quinolines by in situ production of
> 4-Li
> derivatives (with butyl lithium) then reacting
> with
> ester or nitrile in ether at -75oC then
> treating with
> water to hydrolyse the addition product. Each
> time I
> am failing. Would anybody give me any
> suggestion where
> I can take necessary measures or an
> alternative method
> if any. I am using the ether dried with Na and
> tested
> with benzophenone to be dry which is collected
> in the
> molecular seives thus it is supposed to be
> really dry.
> The esters and nitriles are prepared and
> distilled and
> all the reagents are completely dry as all
> reagents
> and vessels have been oven dried and then left
> under
> vacuum dessicator o/n before the reaction
> started.
>
> Thanks for your kind help in this misterious
> chemical
> world
>
> Md Omar Faruk Khan
> Postdoctoral research associate
> University of Misissippi
>
>
>
>
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