From: Clyde Davies (deadlyvices$##$hotmail.com)
Date: Mon Apr 10 2006 - 15:02:37 EDT
I remember doing some perfluoralkylations years ago using sodium salts of
perfluorocarboxylic acids. These were ruined by the presence of water, and
the literature procedure recommended adding dry benzene to the reaction
mixture then distilling it off using a Dean-Stark apparatus prior to heating
up. This removed any traces of water whatsoever. If you try this, and it
still doesn't work, then you know that water isn’t the culprit.
As someone who has had horrible problems with DMF, it is best dried using
CaH2 prior to vacuum distillation but azeotropic drying with benzene also
works very well.
-----Original Message-----
From: everybody-bounces$##$orglist.net [mailto:everybody-bounces$##$orglist.net]
On Behalf Of Jacobo Cruces
Sent: 06 April 2006 09:06
To: everybody$##$orglist.net
Subject: ORGLIST: Cuprate generation from copper
Dear all,
We are trying to generate a cuprate from an aromatic iodide and copper(0),
and then quench the reaction with an electrophile (a gas). The experimental
procedure states that both the substrate and the copper in DMF are
introduced into a Parr reactor, and then the electrophile is introduced and
the reaction heated up to 150 ºC. However, we have no reaction at all: 0%
yield. We are recovering the starting material UNCHANGED. We don't know if
the reaction failure comes from an incorrect purge (O2 or water in the
reaction medium), or if there is some problem with the copper. We are using
copper 40 Mesh purchased from Aldrich (28,608-6).
My question is: can anybody give us a hint about why the reaction does not
work?
Best regards,
Visit us at BioFine 2006 in Barcelona, next May 4-5, Stand B1 !
Dr. Jacobo Cruces
Research Manager
GalChimia, S.L.
Cebreiro, s/n O Pino
15823 A Coruña
SPAIN
Phone: +34 981 814 506
Fax: +34 981 814 507
Home: www.galchimia.com
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