Highly Enantioselective Hydrosilylation of Aromatic Alkenes
作者:Jakob F. Jensen、Bo Y. Svendsen、Thomas V. la Cour、Henriette L. Pedersen、Mogens Johannsen
DOI:10.1021/ja025617q
日期:2002.5.1
Currently, the most effective and economic way to convert an alkene into an optically active alcohol is the two-step sequence: hydrosilylation/oxidation. Much work has been devoted to elucidating effective catalysts for this process, but hitherto only one effective and highly stereoselective process has been available. Herein we present a novel catalytic system for the asymmetric hydrosilylation of
Palladium-catalysed asymmetric hydrosilylation of styrenes with a new chiral monodentate phosphine ligand
作者:Kenji Kitayama、Yasuhiro Uozumi、Tamio Hayashi
DOI:10.1039/c39950001533
日期:——
hydrosilylation of styrenes (ArCHCHR) with trichlorosilane in the presence of a palladium catalyst (0.1 mol%) bearing a new chiralmonodentatephosphineligand, (S)-2-diphenylphosphino-1,1′-binaphthyl [(S)-H-MOP], followed by oxidation of the resulting 1-aryl-1-silylalkanes, gives opticallyactive benzylic alcohols of up to 96% enantiomeric excess (e.e.).
Asymmetric Hydrosilylation of Styrenes by Use of New Chiral Phosphoramidites
作者:Xinsheng Li、Jianan Song、Dongcheng Xu、Lichun Kong
DOI:10.1055/s-2008-1032199
日期:2008.3
Newchiral phosphoramidites were synthesized from chiral unsymmetrical amines and BINOL in good yields. Enantioselective hydrosilylation of styrenes with trichlorosilane in the presence of palladium complexes of these ligands provided chiral silanes in medium to high yields. Oxidation of these chiral silanes with hydrogen peroxide gave the corresponding chiral secondary alcohols in up to 97% ee.
In the palladium-catalyzed asymmetric hydrosilylation of styrene with trichlorosilane, several chiral monophosphine ligands, (R)-2-diarylphosphino-1,1′-binaphthyls (2), were examined for their enantioselectivity. The highest enantioselectivity was observed in the reaction with (R)-2-bis[3,5-bis(trifluoromethyl)phenyl]phosphino-1,1′-binaphthyl (2g), which gave (S)-1-phenylethanol of 98% ee after oxidation of the hydrosilylation product.
Helical Poly(quinoxaline-2,3-diyl)s Bearing Metal-Binding Sites as Polymer-Based Chiral Ligands for Asymmetric Catalysis
作者:Takeshi Yamamoto、Michinori Suginome
DOI:10.1002/anie.200803719
日期:2009.1.5
Living it up: Helical polyquinoxalines with single and multiple metal‐binding sites, prepared by living polymerization of o‐diisocyanobenzenes, are used in the asymmetric hydrosilylation of styrenes, resulting in comparable enantioselectivities to those obtained by low‐molecular‐weight catalyst systems (up to 87 % ee, stereochemistry was determined by a chiral initiator) and a turnover number of almost