From: andrea gansz (andrea.gansz$##$mail.uni-oldenburg.de)
Date: Fri Oct 22 1999 - 07:36:44 EDT
hello orglist,
I think he´s talking about a lactone. If so, yes, it can be done (I onc=
e
did a Wittig-type reaction with glucono-1,4-lactone, DMF, threefold
excess of ethoxymethylcarbonylmethylenetriphenylphosphorane, 140 °C),
but the yields are often poor (due to side-reactions) and you might have
to employ harsher reaction conditions (greater excess of reagent,
elevated temperature) than you would using in rxs with aldehydes or
ketones. How about Grignard (with exactly one eq. of grignard reagent to
prevent disubstituion) and subsequent elimination as an alternative?
A.G.
"Ilfir R. Ramazanov" schrieb:
>
> Hello,
>
> I don't understand did you say about a cyclic ester with C=O group?
>
> you wrote:
> bl> Dear colleagues,
> bl> I have a weird idea. wittig reaction can be easily performed on ket=
one or
> bl> aldehyde. can anyone please tell me if is possible for a cyclic est=
er?! if
> bl> not, is it because the reaction simply can't happen or fear of hydr=
olysis
> bl> (saponification) that may take place?
> bl> Please advice and thanks in advance.
>
> bl> Regards,
> bl> barnabas
>
> Best regards,
> Ilfir R. Ramazanov, Ph.D.,
> Laboratory of Catalytic Synthesis
> Institute of Petrochemistry and Catalysis,
> pr. Oktyabrya, 141,
> Ufa, 450075, Russia.
>
> mailto:elf$##$anrb.ru
>
> Visit my homepage and find some QC software
> http://members.tripod.com/~ChemELF
>
> Visit our lab web page
> http://organomet.cjb.net
>
> 22.10.1999 16:35
>
> __________________
>
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