A series of (β-N-sulfonylaminoalkyl)phosphine ligands has been developed and employed for asymmetric palladium-catalyzed hydrosilylation and Heck-type hydroarylation, affording up to 72% ee and 90% yield.
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.
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
High-Molecular-Weight Polyquinoxaline-Based Helically Chiral Phosphine (PQXphos) as Chirality-Switchable, Reusable, and Highly Enantioselective Monodentate Ligand in Catalytic Asymmetric Hydrosilylation of Styrenes
A polyquinoxaline-basedhelical polymer ligand bearing both helical-sense-determining chiral side chains and coordinating diarylphosphino side chains exhibits solvent-dependent formation of P- or M-helical structures, with which either the S- or R-hydrosilylation product was obtained with high (>93% enantiomeric excess) enantioselectivities.