14th Workshop of the Central European Division e.V. of the International Isotope Society

✍ Scribed by Volker Derdau; Jens Atzrodt

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: French
• Weight: 172 KB
• Volume: 50
• Category: Article
• ISSN: 0022-2135
• DOI: 10.1002/jlcr.1453

✦ Synopsis

For a long time, C 2 -symmetric ligands were dominating in asymmetric catalysis. However, more recently it was found that in several metal-catalyzed processes non-symmetric mixed-donor bidentate P,N-ligands are superior to C 2 -symmetric P,P-or N,N-ligands. Especially phosphinooxazolines (PHOX ligands) have proven to be highly versatile, very effective ligands in a number of enantioselective catalytic reactions, including hydrogenation of C ¼ ¼ N and C ¼ ¼ C bonds, Heck reactions, allylic substitutions and conjugate addition to enones. 1 We have found that iridium complexes with PHOX or other chiral P,N-ligands such as 2 and 3, which are efficient catalysts for the asymmetric hydrogenation of olefins. 2 The catalysts are readily prepared, air stable and easy to handle. In contrast to rhodium-and ruthenium-phosphine complexes, they do not require the presence of a coordinating group next to the C ¼ ¼ C bond and, therefore, considerably expand the application range of asymmetric hydrogenation. Promising results have also been obtained with certain functionalized alkenes, furans and benzofurans. In this lecture, the special properties, the scope and recent applications of these catalysts will be discussed.