New Chiral Bis(oxazolinyl)bipyridine Ligand (Bipymox): Enantioselection in the Asymmetric Hydrosilylation of Ketones

Article abstract of DOI:10.1016/S0957-4166(00)86024-3

A homochiral chiral 6,6'-bis(oxazolinyl)-2,2'-bipyridine ligand, bipymox (1), and its rhodium complex were synthesized to examine the enantioselectivity in the asymmetric hydrosilylation of ketones in comparison to other chiral oxazoline ligands such as bis-(oxazolinyl)pyridine, pybox (2), and mono(oxazolinyl)pyridine, pymox (3).The bipymox-rhodium catalyst gave the (S)-absolute configuration of the product 1-phenylethanol (90percent ee) in the reduction of acetophenone with diphenylsilane the same as the pybox-rhodium system but opposite to the pymox-rhodium system.The reduction of 4-tert-butylcyclohexanone was also described.