From: Jim Mitchell (j_mitchell$##$cerilliant.com)
Date: Fri Aug 23 2002 - 11:26:03 EDT
Pd/C w/ H2 is one of the best methods for deprotecting O-benzyl groups and
works almost as well as on N-benzyl also. I would suggest trying to
reprotect, if possible, with something like TBDMS if your compound isn't
reactive to fluoride anion. However, if both are being reduced, I would
think it would be worth your time to try some other systems as below or
Zn/AcOOH.
Good luck
Jim Mitchell
Cerilliant Corporation
-----Original Message-----
From: Jacobo Cruces [SMTP:jacobo.cruces$##$galchimia.com]
Sent: Thursday, August 22, 2002 11:56 AM
To: everybody$##$orglist.net
Subject: ORGLIST:hydrogenation
Dear all:
We are trying to hydrogenate a conjugated double bond in a molecule which
posses a N-benzyl moiety. However, the catalytic hydrogenation at
atmospheric pressure using Pd/C (2,5%) in MeOH is also deprotecting the
N-benzyl (that is because we do NOT want to deprotect the benzyl group, and
the molecule knows that, so of course the reaction works; if we would try
to deprotect the group it would not work; Murphy strikes again). We have
some experience in the reduction of other conjugated double bonds using
Ni/Raney and Mg/MeOH.
Can anybody give us some hints on this?
Dr. Jacobo Cruces
Research Manager
GalChimia, S.L.
Cebreiro, s/n O Pino
15823 A Coruna
SPAIN
Phone: +34 981 814 506
Fax: +34 981 814 507
Home: www.galchimia.com
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