title: Cobalt alkyl complexes of a new family of chiral 1,3-bis(2-pyridylimino)isoindolates and their application in asymmetric hydrosilylation.
abstract: The synthesis of a new family of chiral tridentate monoanionic NNN-pincer ligands based on the 1,3-bis(2-pyridylimino)isoindoline (BPI) framework is reported. Ligands with substituents of varying steric demand were prepared starting from achiral and low priced materials. A kinetic enzymatic resolution was used as a key step for the preparation of enantiomerically pure ligands. In this way, both enantiomers of a given ligand could be produced enantioselectively (>99.5% ee). The corresponding cobalt alkyl complexes were obtained using a pyridine alkyl cobalt precursor complex and were applied in asymmetric hydrosilylation of several prochiral alkylaryl ketones with high yields (up to 100%) and enantioselectivity (up to 91% ee) to give the chiral alcohols after hydrolysis.
authors.affiliation: Anorganisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
authors.forename: Désirée C
authors.initials: DC
authors.lastname: Sauer
authors.forename: Hubert
authors.initials: H
authors.lastname: Wadepohl
authors.forename: Lutz H
authors.initials: LH
authors.lastname: Gade
mesh_terms: D000438:Alcohols / Q000138:chemical synthesis / Q000737:chemistry; D003035:Cobalt / Q000737:chemistry*; D006868:Hydrolysis; D054833:Isoindoles / Q000737:chemistry*; D007659:Ketones / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D017646:Organosilicon Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D011725:Pyridines / Q000737:chemistry*
chemical_list: D000438:Alcohols; D054833:Isoindoles; D007659:Ketones; D009942:Organometallic Compounds; D017646:Organosilicon Compounds; D011725:Pyridines; D003035:Cobalt