Chiral bis(oxazolinylphenyl)amines proved to be efficient auxiliary ligands for iron and cobalt catalysts with high activity for asymmetrichydrosilylation of ketones and asymmetric conjugate hydrosilylation of enones.
Just a little bit: The 1/FeCl2 complex was activated in the presence of Zn and exhibited catalytic activity for the hydrosilanereduction of ketones to give the S‐configured alcohol. In contrast, the mixed‐catalyst system of 1 and Fe(OAc)2 provides the R enantiomer. This approach provides both enantiomers from a single chiral source by the addition of a small amount of Zn.
The synthesis of a new paracyclophane phosphine is described. This ligand was highly efficient in the ruthenium-catalyzed asymmetric hydrogenation of various aromatic and heteroaromatic ketones.
描述了一种新的对环烷膦的合成。该配体在钌催化的各种芳族和杂芳族酮的不对称氢化中非常有效。
Stereocomplementary Asymmetric Reduction of Bulky–Bulky Ketones by Biocatalytic Hydrogen Transfer
作者:Iván Lavandera、Gustav Oberdorfer、Johannes Gross、Stefaan de Wildeman、Wolfgang Kroutil
DOI:10.1002/ejoc.200800103
日期:2008.5
Biocatalysts suitable for the reduction of ketones bearing two sterically demanding substituents (bulky–bulkyketones) at elevated substrate concentration (10 g L–1) were identified. The biocatalysts can be employed in a substrate-coupled approach; thus, a simple alcohol such as ethanol or 2-propanol serves as a hydrogen donor. Both enantiomers are accessible by using either Rhodococcus ruber DSM 44541
Oxidativekineticresolution of racemicsecondaryalcohols by using acetone as a hydrogen acceptor in the presence of a catalytic amount of [RuCl(2)(PPh(3))(ferrocenyloxazolinylphosphine)] (2) proceeds effectively to recover the corresponding alcohols in high yields with an excellent enantioselectivity. When 1-indanol is employed as a racemicalcohol, the oxidation proceeds quite smoothly even in the