Title: Samarium diiodide, a tool in the area of asymmetric synthesis

Speaker:Prof. Henri B. Kagan

Time:2008.09.26  10:00am

Address:Main Auditorium of  ICCAS

Biographical Sketch

In 1971, Prof. H. Kagan gave the first example of asymmetric synthesis using circularly polarized light (CPL) by synthesizing helicenes. He also realized kinetic resolution with CPL (1974), in confirmation of the pioneer work of W. Kuhn in 1929. He published the first example of a chiral bidentate diphosphine with the synthesis of DIOP in 1971. At this time it provided the highest ee's in hydrogenation and was followed in literature by a cascade of syntheses of chiral diphosphines. It was also the first case of an efficient C2 symmetry ligand, and stimulated the early development of asymmetric catalysis. He described the first example of a chiral " homogeneous " supported catalyst, by the synthesis and use of a DIOP fragment covalently bounded to a Merrifield resin (1973). He introduced in 1986 (in a joint work with Prof. Agami, Paris) the concept of nonlinear effects in asymmetric catalysis. He gave some mathematical models (1994) as well as some further examples. These effects are as now quite popular. In 1984 he modified the Sharpless reagent and obtained good results (90% ee) for asymmetric oxidation of sulfides by hydroperoxides. In 1996 a catalytic system was set up. Various efficient asymmetric syntheses of ferrocenes with planar chirality (ee > 98%) were developed since the last five years. These syntheses are especially useful to prepare new ligands for asymmetric catalysis. Various approaches in organic synthesis have been also investigated, such as the use of reagents incorporated into graphite or the use of lanthanide derivatives. The first paper in this last area (1975) studied air oxidations catalyzed by some Ln(III) nitrates. In 1977 he set up a mild preparation of diiodosamarium and established its usefulness as reducing agent. This reagent became widely used in organic synthesis.

His present research is essentially oriented toward goals connected to chirality, stereochemistry, asymmetric catalysis or stoichiometric asymmetric synthesis.

His awards include the Le Bel award (French Chemical Society, 1967), Cahours Award from French Academy of Science (1968), Silver medal of CNRS (1979), Raymond Berr award (1976), " Rayonnement Français " award (1989), Prelog medal (ETH Zürich, 1990), August-Wilhelm-von-Hofmann medal (Germany, 1991), Francqui Chair (Louvain-la-Neuve, 1994), Chevalier de l'Ordre National du Mérite (1996), Yamada Prize (Tokyo, 1998), 1998 Chirality medal (14th ISCD, Vienna), Nagoya medal of Organic Chemistry (Nagoya, 1998), Tanaka award (International Precious Metals Institute, 1999), Tetrahedron prize for creativity in organic chemistry (1999), Doctor Honoris Causa of Bucarest University (1999), the Silver medal of Centenary lecturer award of the Royal Society of Chemistry (2000), Honorary Fellow of Chemical Research Society of India (2000), Wolf prize in chemistry (2001), Chevalier de la Légion d'Honneur (2002), Grand Prix de la Fondation de la Maison de la Chimie (2002), JSPS Award for Eminent Scientists (2002), Ryoji Noyori prize (2002), Honorary Fellow of RSC (2003).