Asymmetric Transfer Hydrogenation of 1-Naphthyl Ketones by an ansa-Ru(II) Complex of a DPEN-SO2N(Me)-(CH2)2(η6-p-Tol) Combined Ligand
摘要:
The first second-generation designer Ru(II) catalyst 1b featuring an enantiopure N,C-(N-ethylene-N-methyl-sulfamoyI)-tethered (DPEN-k(2)N,N)/n(6)toluene hybrid ligand Is introduced. Using an SIC 1000 in HCO2H Et3N 5:2 transfer hydrogenation medium, secondary 1-naphthyl alcohols are obtained in up to >99.9% ee under mild conditions. Mechanistic factors are discussed.
Enantioselective Hydrogenation of β-Keto Esters using Chiral Diphosphine-Ruthenium Complexes: Optimization for Academic and Industrial Purposes and Synthetic Applications
作者:V. Ratovelomanana-Vidal、C. Girard、R. Touati、J. P. Tranchier、B. Ben Hassine、J. P. Genêt
DOI:10.1002/adsc.200390021
日期:2003.1
Enantioselectivehydrogenationusingchiralcomplexes between atropisomeric diphosphines and ruthenium is a powerful tool for producing chiral compounds. Using a simple and straightforward in situ catalyst preparation, the conditions were optimizedusing molecular hydrogen for both academic and industrialpurposes. This led to the best conditions and the lowest catalytic ratio required for the pressure
Lewis Base Activation of Lewis Acids: Catalytic, Enantioselective Addition of Silyl Ketene Acetals to Aldehydes
作者:Scott E. Denmark、Gregory L. Beutner、Thomas Wynn、Martin D. Eastgate
DOI:10.1021/ja047339w
日期:2005.3.1
The concept of Lewisbase activation of Lewisacids has been reduced to practice for catalysis of the aldolreaction of silyl ketene acetals and silyl dienol ethers with aldehydes. The weakly acidic species, silicon tetrachloride (SiCl4), can be activated by binding of a strongly Lewis basic chiral phosphoramide, leading to in situ formation of a chiral Lewisacid. This species has proven to be a competent
decarboxylative aldol reaction between malonic acid half-oxyesters and various carbonyls with carboxylate assistance was developed, affording structurally diverse β-hydroxy esters with good yields and enantioselectivities under mild conditions. Importantly, the broad substrate scope of this methodology enabled rapid accesses to several natural products and their analogues as exemplified by phenylpropanoid, phaitanthrin
Lewis Base Activation of Lewis Acids. Addition of Silyl Ketene Acetals to Aldehydes
作者:Scott E. Denmark、Thomas Wynn、Gregory L. Beutner
DOI:10.1021/ja0282947
日期:2002.11.1
olefinic aldehydes as well as aliphatic aldehydes (albeit more slowly) with excellent enantioselectivity. The homologous tert-butyldimethylsilyl ketene acetal of tert-butyl propanoate adds with nearly exclusive anti diastereoselectivity to a similar range of aldehydes also with excellent enantioselectivity. The origin of the slower reaction rate with aliphatic aldehydes is revealed to be the formation of chlorosilyl
Chiral Nitroarenes as Enantioselective Single-Electron-Transfer Oxidants for Carbene-Catalyzed Radical Reactions
作者:Hongling Wang、Yuhuang Wang、Xingkuan Chen、Chengli Mou、Shuyan Yu、Huifang Chai、Zhichao Jin、Yonggui Robin Chi
DOI:10.1021/acs.orglett.9b02736
日期:2019.9.20
A new class of chiral oxidants is developed. These readily accessible oxidants contain a nitro group for oxidation and a chiral sulfonamide moiety for stereoselectivity control. The chiral information from the oxidants can effectively transfer to the substrates in carbene-catalyzed β-hydroxylation of enals via single-electron-transfer radical processes. We expect these oxidants to find unique applications