Heterogeneous asymmetric catalysis
M. Lemaire
Laboratoire de Catalyse et
Synthese Organique UCBLCNRS, UMR 5622, CPE,
43 boul.11 Novembre, 69622 Villeurbanne Cédex, France
Abstract: Examples of enantioselective catalysts, including
homogeneous supported catalysts and biphasic liquid/liquid, are described
and compared. In the case of asymmetric hydride transfer, polythiourea
was proven to be more efficient for ruthenium-catalyzed reduction of
arylketones, although the iridium complexes gave rise to higher ee when
using amino sulfonamide bound to a polystyrene matrix. In the case of
asymmetric reduction, the modification of the binap allows the formation
of a polymer that could be used as a catalyst precursor and exhibits
enantioselectivities as high as observed in solution, but easier to
separate and recycle. Bisoxazoline bound to silica particules could
also be used in copper-catalyzed asymmetric Diels-Alder reaction and
cyclopropanation with selectivities similar to that obtained in solution.
*Plenary and invited lectures presented at the 12th
International Symposium on Organometallic Chemistry Directed Towards
Organic Synthesis (OMCOS-12), Toronto, Ontario, Canada, 6-10 July 2003.
Other lectures are published in this issue, pp.
453-695.
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