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.
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.).
When Chirality Meets “Buchwald-Type” Phosphines: Synthesis and Evaluation in Frustrated Lewis Pair-, Lewis Base- and Palladium-Promoted Asymmetric Catalysis
作者:Mickaël J. Fer、Joséphine Cinqualbre、Julien Bortoluzzi、Matthieu Chessé、Frédéric R. Leroux、Armen Panossian
DOI:10.1002/ejoc.201600727
日期:2016.9
“Buchwald ligand”-like biphenylphosphines in highly enantioenriched form. These monodentate phosphines, biphenyl analogues of Hayashi's MOP ligands, were evaluated in phosphine-promoted organocatalysis and in hydrosilylations catalyzed by palladium or by frustrated Lewis pairs. As expected, the title phosphines appeared best suited for transition metal catalysis where they provided higher asymmetric induction
A Versatile Approach to Planar Chiral Monophosphane Ligands
作者:Susan Gibson、Jacob Rendell、Matthew Rudd
DOI:10.1055/s-2006-950291
日期:2006.11
The enantioselective reaction of a chiral bisamide and an electrophile with benzylether complexes of arene tricarbonyl chromium(0) was used to introduce the asymmetry into a synthesis of novel enantiopure planar chiral ligands. Elaboration of the resulting ether complexes [η 6 -4-t-BuC 6 H 4 CHE 1 (OR)]Cr(CO)3 via a diastereoselective ortholithiation/chlorophosphane quench protocol led to the synthesis
手性双酰胺和亲电试剂与芳烃三羰基铬 (0) 的苄基醚配合物的对映选择性反应用于将不对称性引入新型对映纯平面手性配体的合成中。通过非对映选择性正锂化/氯膦淬灭方案制备得到的醚配合物 [η 6 -4-t-BuC 6 H 4 CHE 1 (OR)]Cr(CO)3 导致合成具有高对映体纯度的平面手性单膦配合物(通常为 96-98% ee)用于评估钯催化的苯乙烯不对称氢化硅烷化。发现苄基取代基 E 1 的身份(使用手性碱反应安装)对所得催化剂的对映选择性有显着影响。