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ABSTRACT: Asymmetric hydrogenation: The title reaction provides an efficient and rapid access to chiral 1- and 3-substituted 1,2,3,4-tetrahydroisoquinolines with excellent enantioselectivity (see scheme; L=ligand). A preliminary mechanistic study indicates that the 1,2-hydride addition might be the initial step in the reaction. The method has been used in the synthesis of urinary antispasmodic drug (+)-solifenacin.
Angewandte Chemie International Edition 02/2013; · 13.45 Impact Factor
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ABSTRACT: A novel and efficient method for the generation of o-quinone methide intermediates was developed from the readily available 2-tosylalkylphenols under the mild basic conditions, and their reactions with sulfur ylides were investigated for the stereoselective synthesis of trans-2,3-dihydrobenzofurans.
Chemical Communications 01/2013; · 6.17 Impact Factor
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ABSTRACT: The transition metal catalyzed asymmetric hydrogenation of unsaturated compounds arguably presents one of the most attractive methods for the synthesis of chiral compounds. Over the last few decades, Pd has gradually grown up as a new and popular metal catalyst in homogeneous asymmetric hydrogenation the same as traditional Ru, Rh and Ir catalysts. Much progress has been successfully achieved in the asymmetric reduction of imines, enamines, olefins, ketones and heteroarenes. It was also found that palladium catalyzed asymmetric hydrogenation could be used as a key step in tandem reactions to quickly synthesize chiral compounds. This tutorial review intends to offer an overview of recent progress in homogeneous palladium catalyzed asymmetric hydrogenation and should serve as an inspiration for further advances in this area.
Chemical Society Reviews 11/2012; · 28.76 Impact Factor
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ABSTRACT: Highly efficient iridium-catalyzed asymmetric hydrogenations of simple 2-substituted pyridinium salts gives the chiral 2-substituted piperidines with up to 93 % ee (see picture; cod=1,5-cyclooctadiene; synphos=(5,6),(5',6')-bis(ethylenedioxy)-2,2'-bis(diphenylphosphino)-1,1'-biphenyl). The key feature of this strategy is the activation of simple pyridines as the pyridinium salts, thus eliminating substrate inhibition and enhancing the reactivity.
Angewandte Chemie International Edition 09/2012; 51(40):10181-4. · 13.45 Impact Factor
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ABSTRACT: Highly enantioselective Ir-catalyzed hydrogenation of seven-membered cyclic imines of benzodiazepinones and benzodiazepines was achieved with up to 96% ee. This method provides a direct access to synthesize a range of chiral cyclic amines existing in numerous important natural products and clinical drugs.
Organic Letters 07/2012; 14(15):3890-3. · 5.86 Impact Factor
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ABSTRACT: Reining in the outliers: An efficient approach for enantioselective hydrogenation of 3,4-disubstituted isoquinolines was successfully developed. When isoquinolines are treated with [Ir(cod)Cl](2) /(R)-synphos in the presence of 1-bromo-3-chloro-5,5-dimethyl-hydantoin (BCDMH), the chiral 3,4-disubstituted tetrahydroisoquinoline derivatives are obtained with ee values as high as 96 % (see scheme; cod=1,5-cyclooctadiene).
Angewandte Chemie International Edition 07/2012; 51(33):8286-9. · 13.45 Impact Factor
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ABSTRACT: A new and easily regenerable NAD(P)H model 9,10-dihydrophenanthridine (DHPD) has been designed for biomimetic asymmetric hydrogenation of imines and aromatic compounds. This reaction features the use of hydrogen gas as terminal reductant for the regeneration of the DHPD under the mild condition. Therefore, the substrate scope is not limited in benzoxazinones; the biomimetic asymmetric hydrogenation of benzoxazines, quinoxalines, and quinolines also gives excellent activities and enantioselectivities. Meanwhile, an unexpected reversal of enantioselectivity was observed between the reactions promoted by the different NAD(P)H models, which is ascribed to the different hydride transfer pathway.
Journal of the American Chemical Society 02/2012; 134(4):2442-8. · 9.91 Impact Factor
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ABSTRACT: Asymmetric hydrogenolysis of racemic tertiary alcohols, 3-substituted 3-hydroxyisoindolin-1-ones, was developed using chiral phosphoric acid as catalyst and a Hantzsch ester as the hydrogen source with up to 95% ee. The reaction process of this asymmetric transfer hydrogenation may occur directly through the acyliminium ion intermediate.
Chemical Communications 12/2011; 48(11):1698-700. · 6.17 Impact Factor
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Chemistry 06/2011; 17(26):7193-7. · 5.93 Impact Factor
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ABSTRACT: A highly enantioselective Pd-catalyzed partial hydrogenation of simple 2,5-disubstituted pyrroles with a Brønsted acid as an activator has been successfully developed, providing chiral 2,5-disubstituted 1-pyrrolines with up to 92% ee.
Journal of the American Chemical Society 06/2011; 133(23):8866-9. · 9.91 Impact Factor
