Metal-complexes of optically active amino- and imino-based pyridine ligands in asymmetric catalysis

Metal-complexes of chiral amino- and imino-based pyridine ligands have become a large and important topic in a wide range of asymmetric catalytic processes, such as addition of organozinc reagents to aldehydes, Henry reaction, allylic substitution, hydrogenation by hydrogen transfer, dihydroxylation, epoxidation, etc. This review for the first time provides their applications in asymmetric catalysis in an exhaustive manner. The discussion is generally limited to ligands in which the pyridine ring and the amino or imino nitrogen are connected by a carbon bonded only to hydrogen or carbon atoms and having almost a stereogenic element linked to the amino- or imino-nitrogen. Chiral pyridine ligands derived from picolinamide and those in which the amino or imino nitrogen are inserted in a heterocyclic ring containing other heteroatoms are not included in this account. (C) 2012 Elsevier B.V. All rights reserved.