A concise synthesis of a new xylyl-biaryl diphosphine ligand for asymmetric hydrogenation of ketones

Henschke, Julian P.; Zanotti‐Gerosa, Antonio; Moran, Paul H.; Harrison, Paul; Mullen, Brendan; Casy, Guy; Lennon, Ian C.

doi:10.1016/s0040-4039(03)00940-7

Cited by 41 publications

(14 citation statements)

References 20 publications

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“…The positioning of the substituents on the aromatic ring of acetophenone had significant effect on the outcome of reactions. The ortho-substituted acetophenones (2d-2f ) were converted to the desired alcohols with moderate enantioselectivities (70-77% ee, Table 2, entries 3-5), whereas meta-and para-substituted acetophenones (2g-2o) gave consistently high enantioselectivities (87-97% ee, Table 2, entries [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20].…”

Section: Resultsmentioning

confidence: 99%

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A remarkably effective copper(II)-dipyridylphosphine catalyst system for the asymmetric hydrosilylation of ketones in air

Chan

2005

Proc. Natl. Acad. Sci. U.S.A.

105

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The combination of catalytic amounts of optically active dipyridylphosphine and CuF 2 along with hydride donor PhSiH3 generated in situ a remarkably reactive catalyst system (substrate-toligand molar ratio up to 100,000) for the highly enantioselective hydrosilylation of a broad spectrum of aryl alkyl ketones (up to 97% enantiomeric excess) in normal atmosphere and at mild conditions (ambient temperature to ؊20°C, compatible with traces of moisture) in the absence of base additives. Furthermore, a highly effective catalytic asymmetric hydrosilylation of unsymmetrical diarylketones using this catalyst system was also realized (up to 98% enantiomeric excess). The introduction of the dipyridylphosphine ligands in the air-accelerated and inexpensive metal-mediated asymmetric hydrosilylation of ketones makes the present system highly attractive and thus provides an excellent opportunity for practical applications.asymmetric catalysis C onsiderable efforts have been devoted to the development of efficient methods for the preparation of enantiomerically pure secondary alcohols because of the significance of these intermediates for the manufacture of pharmaceuticals and advanced materials. The catalytic asymmetric reduction of prochiral ketones as a direct route to enantiomeric alcohols is among the most attractive, and various strategies have been developed accordingly (1-5). Although intensive studies have been focused on the asymmetric hydrogenation that shows excellent enantioselectivities for a wide range of simple ketones (refs. 6 and 7 and references therein and refs. 8 -18), asymmetric hydrosilylation as a desirable alternative has also attracted much attention, owing to the mild reaction conditions used and technical simplicity (1d). Since the early reports three decades ago (19 -23), the asymmetric hydrosilylations of prochiral simple ketones mediated by catalysts of rhodium(I) (4, 24 -28) and ruthenium(II) (29, 30) as well as some less expensive metals such as titanium (31-34), zinc (35), tin (36), and copper(I) (37) have been extensively explored. However, most of these reactions were routinely conducted at a low substrate-to-ligand (S͞L) ratio (50 to 500). The high cost of catalyst and the low substrate-to-catalyst ratio rendered the previous hydrosilylation work unattractive commercially. More recently, a significant breakthrough in this area was achieved by , who developed a very effective catalyst system formed in situ from CuCl and nonracemic bidentate phosphines [e.g., (6,6Ј-dimethoxybiphenyl-2,2Ј-diyl)bis[di(3,5-dimethylphenyl)phosphine] (41, 42) or (4,4Ј-bi-1,3-benzodioxol)-5,5Ј-diylbis(di(3,5-di-tert-4-methoxyphenyl)phosphane) (43)] along with t-BuONa. This system allowed for highly active and enantioselective hydrosilylations of both aryl alkyl and heteroaromatic ketones in the presence of an inexpensive stoichiometric reductant polymethylhydrosiloxane (44) even at a S͞L molar ratio up to 100,000, which approached the levels achieved in related ruthenium-based asymmetric hydrogenations (ref. 6 and ...

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Section: Resultsmentioning

confidence: 99%

“…1 H NMR, 13 C NMR, and 31 P NMR spectra were recorded in CDCl 3 on a Varian AS 500 NMR spectrometer (500, 202, and 125 MHz, respectively) at room temperature. The conversions and ees of the asymmetric hydrosilylation products were determined by NMR, chiral GC, and HPLC.…”

Section: Methodsmentioning

confidence: 99%

A remarkably effective copper(II)-dipyridylphosphine catalyst system for the asymmetric hydrosilylation of ketones in air

Chan

2005

Proc. Natl. Acad. Sci. U.S.A.

105

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“…Using trans -RuCl 2 [( S ) -XylBINAP] [( S ) -daipen]/base combined catalyst, the asymmetric hydrogenation of aromatic -heteroaromatic ketones has been applied for the synthesis of chiral drugs, PDE -IV inhibitor (Scheme 7.12 ) [299] . Analogous catalysts with other types of chiral ligands such as BICP [46f] , Xylyl -PHANEPHOS [59c] , Xyl -P -Phos [300] , Xyl -TetraPHEMP [301] , and SDP [302] are also effective to a much lesser degree. For example, the Ru complexes of BICP type of ligands 22 and 23 combined with nonchiral 2 -(alkylthio)amine or 1,2 -diamine have shown good performances for the highly enantioselective hydrogenation of aryl ketones in the presence of alkoxides as the base [276] .…”

Section: Aromatic Ketonesmentioning

confidence: 99%

Transition Metal‐Catalyzed Homogeneous Asymmetric Hydrogenation

Gao

Zhang

2010

Catalytic Asymmetric Synthesis

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INTRODUCTIONAmong all the catalytic asymmetric methodologies to chiral compounds, homogenous transition metal -catalyzed asymmetric hydrogenation plays a particularly important role [1] . Its highly effi cient, environmental friendly, and cost -effective natures have undoubtly made it one of the most studied methodologies during the past 40 years. As a result, the vast number of catalytic systems developed has also had a signifi cant impact on other areas of asymmetric catalysis [2] . More signifi cantly, the achievements from academia research on asymmetric hydrogenation were frequently acknowledged with industrial applications, which, in turn, provide an important driving force for its basic research [3] .Hundreds of catalytic systems have been developed since the seminal discoveries from Knowles and Sabacky [4] , Kagan and Dang [5] , and Horner et al. [6] . In many cases, series of chiral catalysts were developed based on the similar scaffolds and were prepared for the same reactions. Although these analogous ligands are more likely prepared for the purpose of patent protection other than academic curiosity, they indeed provide us an excellent opportunity to compare, evaluate, and study every aspect of the catalysts in asymmetric hydrogenation. In the meantime, a large number of prochiral unsaturated compounds have been successfully hydrogenated with excellent enantioselectivities. Practical applications with very low catalyst loadings and complex substrate structures have continued to emerge since the publication of the last edition of this book.

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“…Inspired by the high potential of the practical application of the P-Phos family ligands, we developed an analog of P-Phos, an electro-rich bipyridyl diphosphine ligand 2,2',6,phosphino]-3,3'-bipyridyl) (Scheme 2, S-2) and explored the Ru-(MeO-P-Phos) catalyzed hydrogenation of aromatic ketones.…”

Section: Scheme 1 P-phos and Its Derivatesmentioning

confidence: 99%

“…Burk and his co-workers 4 reported that PhanePhos-Ru-diamine complexes also showed high activity and enantioselectivity to the asymmetric hydrogenation of many kinds of simple ketones. In 2003, and Xyl-TetraPHEP 6 and excellent results were achieved in the stereoselective hydrogenation of acetophenone. Fan et al 7 reported the dendritic BINAP type ligands for recycling but only moderate ee values were achieved.…”

Section: Introductionmentioning

confidence: 99%

Enantioselective Hydrogenation of Aromatic Ketones Catalyzed by Ru Complex Using a New Bipyridyl Diphosphine

Chen

Ming

et al. 2008

Chin. J. Chem.

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A concise synthesis of a new xylyl-biaryl diphosphine ligand for asymmetric hydrogenation of ketones

Cited by 41 publications

References 20 publications

A remarkably effective copper(II)-dipyridylphosphine catalyst system for the asymmetric hydrosilylation of ketones in air

A remarkably effective copper(II)-dipyridylphosphine catalyst system for the asymmetric hydrosilylation of ketones in air

Transition Metal‐Catalyzed Homogeneous Asymmetric Hydrogenation

Enantioselective Hydrogenation of Aromatic Ketones Catalyzed by Ru Complex Using a New Bipyridyl Diphosphine

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