Highly Enantioselective Hydrosilylation of Aromatic Alkenes
Jakob F. Jensen, Bo Y. Svendsen, Thomas V. la Cour, Henriette L. Pedersen and Mogens Johannsen*
*Department of Chemistry, Technical University of Denmark, Building 201,
DK-2800 Kgs Lyngby, Denmark, Email: mj
kemi.dtu.dk
J. F. Jensen, B. Y. Svendsen, T. V. la Cour, H. L. Pedersen, M. Johannsen, J. Am. Chem. Soc., 2002, 124, 4558-4559.
DOI: 10.1021/ja025617q
Abstract
A novel catalytic system for the asymmetric hydrosilylation of aromatic alkenes is described, which leads to silanes in high yields and with excellent enantioselectivity. The reaction works efficiently for a variety of substituted aromatic alkenes, giving access after Tamao oxidation to almost optically pure benzylic alcohols in high yields.
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Details
The document discusses the highly enantioselective hydrosilylation of aromatic alkenes using palladium-catalyzed reactions. The process involves the addition of a hydrosilane to an alkene in the presence of an optically active palladium complex, resulting in a chiral organosilane. This can be further oxidized to produce chiral alcohols with high enantiomeric excess. The study highlights the development and testing of various ligands, including monophosphine and phosphoramidite ligands, for their efficiency in this reaction. Notably, the phosphoramidite ligand 8 demonstrated the highest enantioselectivity (99% ee) in the hydrosilylation of styrene. The research also explored the reaction's scope with different substituted styrenes, achieving excellent yields and enantioselectivity across various substrates. The findings present a novel catalytic system for the asymmetric hydrosilylation of aromatic alkenes, offering a highly efficient method for synthesizing optically pure benzylic alcohols. The work was supported by several Danish research councils and pharmaceutical companies.
Key Words
Benzylsilanes, Tamao Oxidation
ID: J48-Y2002-1100
