Methods for the asymmetric transfer hydrogenation (ATH) of ketones and imines are still being intensively studied and developed. Of foremost interest is the use of Noyori's [RuCl(η⁶-arene)(N-TsDPEN)] complexes in the presence of a hydrogen donor (i-PrOH, formic acid). These complexes have found numerous practical applications and have been extensively modified. The resulting derivatives have been heterogenized, used in ATH in water or ionic liquids and even some attempts have been made to approach the properties of biocatalysts. Therefore, an appropriate modification of the catalyst that suits the specific requirements for the reaction conditions is very often readily available. The mechanism of the reaction has also been explored to a great extent. Model substrates, acetophenone (a ketone) and 6,7-dimethoxy-1-methyl-3,4-dihydroisoquinoline (an imine), are both reduced by this Ru catalytic system with almost perfect selectivity. However, in each case the major product is a different enantiomer (S- for an alcohol, R- for an amine when the S,S-catalyst is used), which demanded an in-depth mechanistic investigation. Full-scale molecular modelling of this system enabled us to visualize the plausible 3D structures of the transition states, allowing the proposition of a viable explanation of previous experimental findings.

Department of Organic Technology Institute of Chemical Technology Technická 5 CZ 16628 Prague Czech Republic

Zobrazit více v PubMed

Davies N.M., Teng X.W. Importance of chirality in drug therapy and pharmacy practice: Implications for psychiatry. Adv. Pharm. 2003;I:242–252.

Arnum P.V. Single-enantiomer drugs drive advances in asymmetric synthesis. Pharm. Technol. 2006;30:58–67.

Lin G.-Q., Li Y.-M., Chan A.S.C. Principles and Applications of Asymmetric Synthesis. John Wiley & Sons, Inc.; New York, NY, USA: 2001.

Liu W. Resolutions at Large Scale: Case Studies. In: Ager D., editor. Handbook of Chiral Chemicals. 2nd ed. CRC Taylor & Francis Group; Boca Raton, FL, USA: 2006. pp. 75–95.

Li Z.J., Grant D.J.W. Relationship between physical properties and crystal structures of chiral drugs. J. Pharm. Sci. 1997;86:1073–1078. PubMed

Subramanian G. Chiral Separation Techniques: A Practical Approach. 3rd ed. Wiley-VCH Verlag GmbH & Co. KGaA; Weinheim, Germany: 2006.

Gladiali S., Alberico E. Asymmetric transfer hydrogenation: Chiral ligands and applications. Chem. Soc. Rev. 2006;35:226–236. doi: 10.1039/B513396C. PubMed DOI

Drauz K., Waldmann H. Enzyme Catalysis in Organic Synthesis. 2nd ed. Wiley-VCH Verlag GmbH; Weinheim, Germany: 2002.

Noyori R. Asymmetric Catalysis In Organic Synthesis. John Wiley & Sons, Inc.; New York, NY, USA: 1994.

Blaser H.-U., Malan C., Pugin B., Spindler F., Steiner H., Studer M. Selective hydrogenation for fine chemicals: Recent trends and new developments. Adv. Synth. Catal. 2003;345:103–151. doi: 10.1002/adsc.200390000. DOI

Ojima I. Catalytic Asymmetric Synthesis. 3rd ed. John Wiley & Sons, Inc.; Hoboken, NJ, USA: 2010.

Noyori R. Asymmetric catalysis: Science and opportunities (Nobel Lecture) Angew. Chem. Int. Ed. 2002;41:2008–2022. doi: 10.1002/1521-3773(20020617)41:12<2008::AID-ANIE2008>3.0.CO;2-4. PubMed DOI

Knowles W.S. Asymmetric hydrogenations (Nobel Lecture) Angew. Chem. Int. Ed. 2002;41:1998–2007. doi: 10.1002/1521-3773(20020617)41:12<1998::AID-ANIE1998>3.0.CO;2-8. PubMed DOI

Knowles W.S., Noyori R. Pioneering perspectives on asymmetric hydrogenation. Acc. Chem. Res. 2007;40:1238–1239. doi: 10.1021/ar7000809. PubMed DOI

Dang T.P., Kagan H.B. The asymmetric synthesis of hydratopic acid and amino-acids by homogeneous catalytic hydrogenation. Chem. Commun. 1971:481. doi: 10.1039/c29710000481. DOI

Kagan H.B., Dang T.-P. Asymmetric catalytic reduction with transition metal complexes. I. A catalytic system of Rhodium(I) with (–)-2,3-O-isopropylidene-2,3-dihydroxy-1,4-bis(diphenylphosphino)butane, a new chiral diphosphine. J. Am. Chem. Soc. 1972;94:6429–6433. doi: 10.1021/ja00773a028. DOI

Knowles W.S., Sabacky M.J., Vineyard B.D. Catalytic asymmetric hydrogenation. J. Chem. Soc. Chem. Commun. 1972:10–11. doi: 10.1039/c39720000010. PubMed DOI

Börner A. Phosphorus Ligands in Asymmetric Catalysis, Synthesis and Applications. WILEY-VCH Verlag GmbH & Co. KGaA; Weinheim, Germany: 2008.

Tang W., Zhang X. New chiral phosphorous ligands for enantioselective hydrogenation. Chem. Rev. 2003;103:3029–3069. doi: 10.1021/cr020049i. PubMed DOI

Helmchen G., Pfaltz A. Phosphinooxazolines – A new class of versatile, modular P,N-ligands for asymmetric catalysis. Acc. Chem. Res. 2000;33:336–345. doi: 10.1021/ar9900865. PubMed DOI

Noyori R., Hashiguchi S. Asymmetric transfer hydrogenation catalyzed by chiral ruthenium complexes. Acc. Chem. Res. 1997;30:97–102. doi: 10.1021/ar9502341. DOI

Murata K., Okano K., Miyagi M., Iwane H., Noyori R., Ikariya T. A practical stereoselective synthesis of chiral hydrobenzoins via asymmetric transfer hydrogenation of benzils. Org. Lett. 1999;1:1119–1121. doi: 10.1021/ol990226a. DOI

Vedejs E., Trapencieris P., Suna E. Substituted isoquinolines by noyori transfer hydrogenation: Enantioselective synthesis of chiral diamines containing an aniline subunit. J. Org. Chem. 1999;64:6724–6729. doi: 10.1021/jo990594s. PubMed DOI

Koike T., Murata K., Ikariya T. Stereoselective synthesis of optically active a-hydroxy ketones and anti-1,2-diols via asymmetric transfer hydrogenation of unsymmetrically substituted 1,2-diketones. Org. Lett. 2000;2:3833–3836. doi: 10.1021/ol0002572. PubMed DOI

Okano K., Muratsugu S., Ikariya T. Stereoselective synthesis of optically active pyridyl alcohols via asymmetric transfer hydrogenation of pyridyl ketones. Tetrah. Lett. 2000;41:9277–9280. doi: 10.1016/S0040-4039(00)01695-6. DOI

Yamada I., Noyori R. Asymmetric transfer hydrogenation of benzaldehydes. Org. Lett. 2000;2:3425–3427. doi: 10.1021/ol0002119. PubMed DOI

Watanabe M., Murata K., Ikariya T. Practical synthesis of optically active amino alcohols via asymmetric transfer hydrogenation of functionalized aromatic ketones. J. Org. Chem. 2002;67:1712–1715. doi: 10.1021/jo011076w. PubMed DOI

Xue D., Chen Y.-C., Cui X., Wang Q.-W., Zhu J., Deng J.-G. Transfer hydrogenation of activated C=C bonds catalyzed by ruthenium amido complexes: Reaction scope, limitation and enantioselectivity. J. Org. Chem. 2005;70:3584–3591. doi: 10.1021/jo0478205. PubMed DOI

Samano V., Ray J.A., Thompson J.B., Mook R.A., Jung D.K., Koble C.S., Martin M.T., Bigham E.C., Regitz C.S., Feldman P.L., et al. Synthesis of ultra-short-acting neuromuscular blocker GW 0430: A remarkably stereo- and regioselective synthesis of mixed tetrahydroisoquinolinium chlorofumarates. Org. Lett. 1999;1:1993–1996. doi: 10.1021/ol9911573. PubMed DOI

Meuzelaar G.J., van Vliet M.C.A., Maat L., Sheldon R.A. Improvements in the total synthesis of morphine. Eur. J. Org. Chem. 1999;1999:2315–2321. doi: 10.1002/(SICI)1099-0690(199909)1999:9<2315::AID-EJOC2315>3.0.CO;2-V. DOI

Miyagi M., Takehara J., Collet S., Okano K. Practical synthesis of (S)-1-(3-trifluoromethylphenyl)ethanol via Ruthenium(II)-catalyzed asymmetric transfer hydrogenation. Org. Proc. Res. Dev. 2000;4:346–348. doi: 10.1021/op000019m. DOI

Tietze L.F., Zhou Y., Töpken E. Synthesis of simple enantiopure tetrahydro-β-carbolines and tetrahydroisoquinolines. Eur. J. Org. Chem. 2000;2000:2247–2252. doi: 10.1002/1099-0690(200006)2000:12<2247::AID-EJOC2247>3.0.CO;2-4. DOI

Szawkalo J., Czarnocki Z. Enantioselective synthesis of some tetracyclic isoquinoline alkaloids by asymmetric transfer hydrogenation catalysed by a chiral ruthenium complex. Monatsh. Chem. 2005;136:1619–1627. doi: 10.1007/s00706-005-0341-8. DOI

Roszkowski P., Wojtasiewicz K., Leniewski A., Maurin J.K., Lis T., Czarnocki Z. Enantioselective synthesis of 1-substituted tetrahydro-b-carboline derivatives via the asymmetric transfer hydrogenation. J. Mol. Catal., A Chem. 2005;232:143–149. doi: 10.1016/j.molcata.2005.01.044. DOI

Roszkowski P., Maurin J.K., Czarnocki Z. Enantioselective synthesis of (R)-(–)-praziquantel (PZQ) Tetrahedron Asymmetry. 2006;17:1415–1419. doi: 10.1016/j.tetasy.2006.04.023. DOI

Szawkalo J., Czarnocki S.J., Zawadzka A., Wojtasiewicz K., Leniewski A., Maurin J.K., Czarnocki Z., Drabowicz J. Enantioselective synthesis of some tetrahydroisoquinoline and tetrahydro-b-carboline alkaloids. Tetrahedron Asymmetry. 2007;18:406–413. doi: 10.1016/j.tetasy.2007.01.014. DOI

Cheng J.-J., Yang Y.-S. Enantioselective total synthesis of (−)-(S)-stepholidine. J. Org. Chem. 2009;74:9225–9228. doi: 10.1021/jo9020826. PubMed DOI

Palmer M.J., Wills M. Asymmetric transfer hydrogenation of C=O and C=N bonds. Tetrahedron Asymmetry. 1999;10:2045–2061. doi: 10.1016/S0957-4166(99)00216-5. DOI

Wills M., Palmer M., Smith A., Kenny J., Walsgrove T. Recent developments in the area of asymmetric transfer hydrogenation. Molecules. 2000;5:4–18. doi: 10.3390/50100004. DOI

Everaere K., Mortreux A., Carpentier J.-F. Ruthenium(II)-catalyzed asymmetric transfer hydrogenation of carbonyl compounds with 2-propanol and ephedrine-type ligands. Adv. Synth. Catal. 2003;345:67–77. doi: 10.1002/adsc.200390030. DOI

Wang C., Wu X., Xiao J. Broader, greener, and more efficient: Recent advances in asymmetric transfer hydrogenation. Chem. Asian J. 2008;3:1750–1770. doi: 10.1002/asia.200800196. PubMed DOI

Nugent T.C., El-Shazly M. Chiral amine synthesis – recent developments and trends for enamide reduction, reductive amination, and imine reduction. Adv. Synth. Catal. 2010;352:753–819. doi: 10.1002/adsc.200900719. DOI

Fleury-Brégeot N., de la Fuente V., Castillón S., Claver C. Highlights of transition metal-catalyzed asymmetric hydrogenation of imines. ChemCatChem. 2010;2:1346–1371. doi: 10.1002/cctc.201000078. DOI

Bäckvall J.-E. Transition metal hydrides as active intermediates in hydrogen transfer reactions. J. Organomet. Chem. 2002;652:105–111. doi: 10.1016/S0022-328X(02)01316-5. DOI

Clapham S.E., Hadzovic A., Morris R.H. Mechanisms of the H2-hydrogenation and transfer hydrogenation of polar bonds catalyzed by ruthenium hydride complexes. Coord. Chem. Rev. 2004;248:2201–2237. doi: 10.1016/j.ccr.2004.04.007. DOI

Samec J.S.M., Backvall J.-E., Andersson P.G., Brandt P. Mechanistic aspects of transition metal-catalyzed hydrogen transfer reactions. Chem. Soc. Rev. 2006;35:237–248. doi: 10.1039/b515269k. PubMed DOI

Fabrello A., Bachelier A., Urrutigoïty M., Kalck P. Mechanistic analysis of the transition metal-catalyzed hydrogenation of imines and functionalized enamines. Coord. Chem. Rev. 2010;254:273–287. doi: 10.1016/j.ccr.2009.09.002. DOI

Sandoval C.A., Ohkuma T., Utsumi N., Tsutsumi K., Murata K., Noyori R. Mechanism of asymmetric hydrogenation of acetophenone catalyzed by chiral η6-Arene-N-tosylethylenediamine-ruthenium(II) complexes. Chem. Asian J. 2006;1:102–110. doi: 10.1002/asia.200600098. PubMed DOI

Sandoval C.A., Bie F., Matsuoka A., Yamaguchi Y., Naka H., Li Y., Kato K., Utsumi N., Tsutsumi K., Ohkuma T., et al. Chiral η6-Arene/N-tosylethylenediamine-ruthenium(II) complexes: Solution behavior and catalytic activity for asymmetric hydrogenation. Chem. Asian J. 2010;5:806–816. doi: 10.1002/asia.200900461. PubMed DOI

Takehara J., Hashiguchi S., Fujii A., Inoue S.-i., Ikariya T., Noyori R. Amino alcohol effects on the ruthenium(II)-catalysed asymmetric transfer hydrogenation of ketones in propan-2-ol. Chem. Commun. 1996:233–234. doi: 10.1039/cc9960000233. DOI

Püntener K., Schwink L., Knochel P. New efficient catalysts for enantioselective transfer hydrogenations. Tetrahedron Lett. 1996;37:8165–8168. doi: 10.1016/0040-4039(96)01853-9. DOI

Hashiguchi S., Fujii A., Takehara J., Ikariya T., Noyori R. Asymmetric transfer hydrogenation of aromatic ketones catalyzed by chiral Ruthenium(II) complexes. J. Am. Chem. Soc. 1995;117:7562–7563. doi: 10.1021/ja00133a037. DOI

Uematsu N., Fujii A., Hashiguchi S., Ikariya T., Noyori R. Asymmetric transfer hydrogenation of imines. J. Am. Chem. Soc. 1996;118:4916–4917. doi: 10.1021/ja960364k. DOI

Fujii A., Hashiguchi S., Uematsu N., Ikariya T., Noyori R. Ruthenium(II)-catalyzed asymmetric transfer hydrogenation of ketones using a formic acid-triethylamine mixture. J. Am. Chem. Soc. 1996;118:2521–2522. doi: 10.1021/ja954126l. DOI

Matsumura K., Hashiguchi S., Ikariya T., Noyori R. Asymmetric transfer hydrogenation of a,b-acetylenic ketones. J. Am. Chem. Soc. 1997;119:8738–8739. doi: 10.1021/ja971570a. DOI

Gladiali S., Alberico E. Transferhydrogenations. In: Beller M., Bolm C., editors. Transition Metals for Organic Synthesis. 2nd ed. Volume 2. Wiley-VCH Verlag GmbH & Co. KGaA; Weinheim, Germany: 2004. pp. 145–166.

Chen Y.-C., Wu T.-F., Deng J.-G., Liu H., Cui X., Zhu J., Jiang Y.-Z., Choi M.C.K., Chan A.S.C. Multiple dendritic catalysts for asymmetric transfer hydrogenation. J. Org. Chem. 2002;67:5301–5306. doi: 10.1021/jo0257795. PubMed DOI

Dwars T., Oehme G. Complex-catalyzed hydrogenation reactions in aqueous media. Adv. Synth. Catal. 2002;344:239–260. doi: 10.1002/1615-4169(200206)344:3/4<239::AID-ADSC239>3.0.CO;2-O. DOI

Wu X., Li X., Hems W., King F., Xiao J. Accelerated asymmetric transfer hydrogenation of aromatic ketones in water. Org. Biomol. Chem. 2004;2:1818–1821. doi: 10.1039/b403627a. PubMed DOI

Wu X., Li X., King F., Xiao J. Insight into and practical application of pH-controlled asymmetric transfer hydrogenation of aromatic ketones in water. Angew. Chem. Int. Ed. 2005;44:3407–3411. doi: 10.1002/anie.200500023. PubMed DOI

Noyori R., Yamakawa M., Hashiguchi S. Metal-ligand bifunctional catalysis: A nonclassical mechanism for asymmetric hydrogen transfer between alcohols and carbonyl compounds. J. Org. Chem. 2001;66:7931–7944. doi: 10.1021/jo010721w. PubMed DOI

Wang F., Liu H., Cun L., Zhu J., Deng J., Jiang Y. Asymmetric transfer hydrogenation of ketones catalyzed by hydrophobic metal-amido complexes in aqueous micelles and vesicles. J. Org. Chem. 2005;70:9424–9429. doi: 10.1021/jo0514826. PubMed DOI

Zhou H.-F., Fan Q.-H., Huang Y.-Y., Wu L., He Y.-M., Tang W.-J., Gu L.-Q., Chan A.S.C. Mixture of poly(ethylene glycol) and water as environmentally friendly media for efficient enantioselective transfer hydrogenation and catalyst recycling. J. Mol. Catal., A Chem. 2007;275:47–53. doi: 10.1016/j.molcata.2007.05.029. DOI

Wang W., Li Z., Mu W., Su L., Wang Q. Highly efficient asymmetric transfer hydrogenation of ketones in emulsions. Catal. Commun. 2010;11:480–483. doi: 10.1016/j.catcom.2009.12.002. DOI

Haack K.-J., Hashiguchi S., Fujii A., Ikariya T., Noyori R. The catalyst precursor, catalyst, and intermediate in the Ru(II)-promoted asymmetric hydrogen transfer between alcohols and ketones. Angew. Chem. Int. Ed. Engl. 1997;36:285–288. doi: 10.1002/anie.199702851. DOI

de Smet K., Pleysier A., Vankelecom I.F.J., Jacobs P.A. Recycling of homogeneous hydrogenation catalysts by dialysis coupled catalysis. Chem. Eur. J. 2003;9:334–338. doi: 10.1002/chem.200390028. PubMed DOI

Šiklová H., Leitmannová E., Kačer P., Červený L. Immobilization of Ru-TsDPEN catalyst on functionalized MCM-41. React. Kinet. Catal. Lett. 2007;92:129–136. doi: 10.1007/s11144-007-5140-2. DOI

Yang H., Li J., Yang J., Liu Z., Yang Q., Li C. Asymmetric reactions on chiral catalysts entrapped within a mesoporous cage. Chem. Commun. 2007:1086–1088. doi: 10.1039/b614635j. PubMed DOI

Yang H., Zhang L., Zhong L., Yang Q., Li C. Enhanced cooperative activation effect in the hydrolytic kinetic resolution of epoxides on [Co(salen)] catalysts confined in nanocages. Angew. Chem. Int. Ed. 2007;46:6861–6865. doi: 10.1002/anie.200701747. PubMed DOI

Yang H., Zhang L., Wang P., Yang Q., Li C. The enantioselective cyanosilylation of aldehydes on a chiral VO(Salen) complex encapsulated in SBA-16. Green Chem. 2009;11:257–264. doi: 10.1039/B815997A. DOI

Yang H., Zhang L., Su W., Yang Q., Li C. Asymmetric ring-opening of epoxides on chiral Co(Salen) catalyst synthesized in SBA-16 through the "ship in a bottle" strategy. J. Catal. 2007;248:204–212. doi: 10.1016/j.jcat.2007.03.006. DOI

Kawasaki I., Tsunoda K., Tsuji T., Yamaguchi T., Shibuta H., Uchida N., Yamashita M., Ohta S. A recyclable catalyst for asymmetric transfer hydrogenation with a formic acid-triethylamine mixture in ionic liquid. Chem. Commun. 2005:2134–2136. doi: 10.1039/B500320B. PubMed DOI

Joerger J.-M., Paris J.-M., Vaultier M. [Ru(arene)(diamine)] catalysts in ionic liquids: Recyclable catalytic systems for transfer hydrogenation. ARKIVOC. 2006:152–160.

Hut’ka M., Toma Š. Hydrogen transfer reduction of different ketones in ionic liquids. Chem. Mon. 2008;139:793–798. doi: 10.1007/s00706-008-0853-0. DOI

Václavík J., Kačer P., Červený L. Rational Design of Chiral Ruthenium Complexes for Asymmetric Hydrogenations. In: Poehler A.C., editor. Homogeneous Catalysts: Types, Reactions and Applications. Nova Science Publishers, Inc.; Hauppauge, NY, USA: 2011. in press.

Hayes A., Clarkson G., Wills M. The importance of 1,2-anti-disubstitution in monotosylated diamine ligands for ruthenium(II)-catalysed asymmetric transfer hydrogenation. Tetrahedron Asymmetry. 2004;15:2079–2084. doi: 10.1016/j.tetasy.2004.05.025. DOI

Yamakawa M., Yamada I., Noyori R. Angew. Chem. Int. Ed. 2001;40:2818–2821. doi: 10.1002/1521-3773(20010803)40:15<2818::AID-ANIE2818>3.0.CO;2-Y. PubMed DOI

Soleimannejad J., Sisson A., White C. Functionalized-arene ruthenium half-sandwich compounds as enantioselective hydrogen transfer catalysts. crystal structures of [RuCl{TsNCH(R)CH(R)NH2}(h6-C6H5OCH2CH2OH)] (R=H or Ph) Inorg. Chim. Acta. 2003;352:121–128. doi: 10.1016/S0020-1693(03)00151-8. DOI

Matsunaga H., Ishizuka T., Kunieda T. Highly efficient asymmetric transfer hydrogenation of ketones catalyzed by chiral ‘roofed’ cis-diamine-Ru(II) complex. Tetrahedron Lett. 2005;46:3645–3648. doi: 10.1016/j.tetlet.2005.03.165. DOI

Li X., Blacker J., Houson I., Wu X., Xiao J. An efficient Ir(III) catalyst for the asymmetric transfer hydrogenation of ketones in neat water. Synlett. 2006;2006:1155,1160. doi: 10.1002/chin.200638079. DOI

Liu J., Wu Y., Li X., Chan A.S.C. Structure effect of TsDPEN derivatives on enantioselectivity of asymmetric transfer hydrogenation. J. Organomet. Chem. 2008;693:2177–2180. doi: 10.1016/j.jorganchem.2008.03.018. DOI

Martins J.E.D., Clarkson G.J., Wills M. Ru(II) complexes of N-alkylated TsDPEN ligands in asymmetric transfer hydrogenation of ketones and imines. Organic Lett. 2009;11:847–850. doi: 10.1021/ol802801p. PubMed DOI

Martins J.E.D., Contreras Redondo M.A., Wills M. Applications of N’-alkylated derivatives of TsDPEN in the asymmetric transfer hydrogenation of C=O and C=N bonds. Tetrahedron Asymmetry. 2010;21:2258–2264. doi: 10.1016/j.tetasy.2010.07.013. DOI

Hannedouche J., Clarkson G.J., Wills M. A new class of “tethered” Ruthenium(II) catalyst for asymmetric transfer hydrogenation reactions. J. Am. Chem. Soc. 2004;126:986–987. doi: 10.1021/ja0392768. PubMed DOI

Cheung F.K., Hayes A.M., Hannedouche J., Yim A.S.Y., Wills M. “Tethered” Ru(II) catalysts for asymmetric transfer hydrogenation of ketones. J. Org. Chem. 2005;70:3188–3197. doi: 10.1021/jo050032a. PubMed DOI

Cheung F.K., Clarke A.J., Clarkson G.J., Fox D.J., Graham M.A., Lin C., Criville A.L., Wills M. Kinetic and structural studies on ‘tethered’ Ru(II) arene ketone reduction catalysts. Dalton Trans. 2010;39:1395–1402. doi: 10.1039/B915932K. PubMed DOI

Morris D.J., Hayes A.M., Wills M. The “reverse-tethered” Ruthenium (II) catalyst for asymmetric transfer hydrogenation: Further applications. J. Org. Chem. 2006;71:7035–7044. doi: 10.1021/jo061154l. PubMed DOI

Kačer P., Kuzma M., Leitmannová E., Červený L. Ruthenium complexes for asymmetric transfer hydrogenation. In: Chin H.F., editor. Organometallic Compounds: Preparation, Structure and Properties. Nova Science Publishers, Inc.; Hauppauge, NY, USA: 2009. pp. 361–387.

Wu X., Xiao J. Aqueous-phase asymmetric transfer hydrogenation of ketones – a greener approach to chiral alcohols. Chem. Commun. 2007:2449–2466. doi: 10.1039/b618340a. PubMed DOI

Wu X., Wang C., Xiao J. Asymmetric transfer hydrogenation in water with platinum group metal catalysts. Platinum Met. Rev. 2010;54:3–19. doi: 10.1595/147106709X481372. DOI

Bubert C., Blacker J., Brown S.M., Crosby J., Fitzjohn S., Muxworthy J.P., Thorpe T., Williams J.M.J. Synthesis of water-soluble aminosulfonamide ligands and their application in enantioselective transfer hydrogenation. Tetrahedron Lett. 2001;42:4037–4039. doi: 10.1016/S0040-4039(01)00623-2. DOI

Thorpe T., Blacker J., Brown S.M., Bubert C., Crosby J., Fitzjohn S., Muxworthy J.P., Williams J.M.J. Efficient rhodium and iridium-catalysed asymmetric transfer hydrogenation using water-soluble aminosulfonamide ligands. Tetrahedron Lett. 2001;42:4041–4043. doi: 10.1016/S0040-4039(01)00624-4. DOI

Ma Y., Liu H., Chen L., Cui X., Zhu J., Deng J. Asymmetric transfer hydrogenation of prochiral ketones in aqueous media with new water-soluble chiral vicinal diamine as ligand. Org. Lett. 2003;5:2103–2106. doi: 10.1021/ol0345125. PubMed DOI

Wu J., Wang F., Ma Y., Cui X., Cun L., Zhu J., Deng J., Yu B. Asymmetric transfer hydrogenation of imines and iminiums catalyzed by water-soluble catalyst in water. Chem. Commun. 2006:1766–1768. doi: 10.1039/b600496b. PubMed DOI

Li L., Wu J., Wang F., Liao J., Zhang H., Lian C., Zhu J., Deng J. Asymmetric transfer hydrogenation of ketones and imines with novel water-soluble chiral diamine as ligand in neat water. Green Chem. 2007;9:23–25. doi: 10.1039/B611809G. DOI

Zhou Z., Ma Q., Sun Y., Zhang A., Li L. Ruthenium(II)-catalyzed asymmetric transfer hydrogenation of aromatic ketones in water using novel water-soluble chiral monosulfonamide ligands. Heteroatom Chem. 2010;21:505–514. doi: 10.1002/hc.20641. DOI

Cross D.J., Kenny J.A., Houson I., Campbell L., Walsgrove T., Wills M. Tetrahedron Asymmetry. 2001;12:1801–1806.

Zhou Z., Sun Y. Water-soluble chiral aminosulfonamides as ligands for ruthenium(II)-catalyzed asymmetric transfer hydrogenation. Catal. Commun. 2009;10:1685–1688. doi: 10.1016/j.catcom.2009.05.013. DOI

Zhou Z., Sun Y., Zhang A. Asymmetric transfer hydrogenation of prochiral ketones catalyzed by aminosulfonamide-ruthenium complexes in ionic liquid. Cent. Eur. J. Chem. 2011;9:175–179. doi: 10.2478/s11532-010-0134-8. DOI

Ter Halle R., Schulz E., Lemaire M. Heterogeneous enantioselective catalytic reduction of ketones. Synlett. 1997:1257–1258. doi: 10.1055/s-1997-1018. DOI

Bayston D.J., Travers C.B., Polywka M.E.C. Synthesis and evaluation of a chiral heterogeneous transfer hydrogenation catalyst. Tetrahedron Asymmetry. 1998;9:2015–2018. doi: 10.1016/S0957-4166(98)00214-6. DOI

Li X., Chen W., Hems W., King F., Xiao J. Asymmetric transfer hydrogenation of ketones with a polymer-supported chiral diamine. Tetrahedron Lett. 2004;45:951–953. doi: 10.1016/j.tetlet.2003.11.104. DOI

Li X., Wu X., Chen W., Hancock F.E., King F., Xiao J. Asymmetric transfer hydrogenation in Wwater with a supported noyori-ikariya catalyst. Org. Lett. 2004;6:3321–3324. doi: 10.1021/ol0487175. PubMed DOI

Liu P.N., Gu P.M., Wang F., Tu Y.Q. Efficient heterogeneous asymmetric transfer hydrogenation of ketones using highly eecyclable and accessible silica-immobilized Ru-TsDPEN catalysts. Org. Lett. 2004;6:169–172. doi: 10.1021/ol036065z. PubMed DOI

Liu P.N., Deng J.G., Tu Y.Q., Wang S.H. Highly efficient and recyclable heterogeneous asymmetric transfer hydrogenation of ketones in water. Chem. Commun. 2004:2070–2071. doi: 10.1039/b408533g. PubMed DOI

Liu P.-N., Gu P.-M., Deng J.-G., Tu Y.-Q., Ma Y.-P. Efficient heterogeneous asymmetric transfer hydrogenation catalyzed by recyclable silica-supported Ruthenium complexes. Eur. J. Org. Chem. 2005;2005:3221–3227. doi: 10.1002/ejoc.200500074. DOI

Li Y., Li Z., Li F., Wang Q., Tao F. Preparation of polymer-supported Ru-TsDPEN catalysts and use for enantioselective synthesis of (S)-fluoxetine. Org. Biomol. Chem. 2005;3:2513–2518. doi: 10.1039/b505943g. PubMed DOI

Huang X., Ying J.Y. Asymmetric transfer hydrogenation over Ru-TsDPEN catalysts supported on siliceous mesocellular foam. Chem. Commun. 2007:1825–1827. doi: 10.1039/B615564B. PubMed DOI

Arakawa Y., Haraguchi N., Itsuno S. Design of novel polymer-supported chiral catalyst for asymmetric transfer hydrogenation in water. Tetrahedron Lett. 2006;47:3239–3243. doi: 10.1016/j.tetlet.2006.03.041. DOI

Haraguchi N., Tsuru K., Arakawa Y., Itsuno S. Asymmetric transfer hydrogenation of imines catalyzed by a polymer-immobilized chiral catalyst. Org. Biomol. Chem. 2009;7:69–75. doi: 10.1039/B815407B. PubMed DOI

Liu J., Zhou Y., Wu Y., Li X., Chan A.S.C. Asymmetric transfer hydrogenation of ketones with a polyethylene glycol bound Ru catalyst in water. Tetrahedron Asymmetry. 2008;19:832–837. doi: 10.1016/j.tetasy.2008.03.015. DOI

Li J., Zhang Y., Han D., Gao Q., Li C. Asymmetric transfer hydrogenation using recoverable ruthenium catalyst immobilized into magnetic mesoporous silica. J. Mol. Catal., A Chem. 2009;298:31–35. doi: 10.1016/j.molcata.2008.09.027. DOI

Zhou Z., Sun Y. Synthesis of polyethylene glycol supported chiral monosulfonamide and its application in asymmetric transfer hydrogenation of prochiral ketones. React. Kinet. Mech. Catal. 2010;99:391–396. doi: 10.1007/s11144-009-0137-7. DOI

Arakawa Y., Chiba A., Haraguchi N., Itsuno S. Asymmetric transfer hydrogenation of aromatic ketones in water using a polymer-supported chiral catalyst containing a hydrophilic pendant group. Adv. Synth. Catal. 2008;350:2295–2304. doi: 10.1002/adsc.200800362. DOI

Liu J., Zhou D., Jia X., Huang L., Li X., Chan A.S.C. A convenient synthesis of (R)-salmeterol via Rh-catalyzed asymmetric transfer hydrogenation. Tetrahedron Asymmetry. 2008;19:1824–1828. doi: 10.1016/j.tetasy.2008.07.021. DOI

Huang L., Liu J., Shan W., Liu B., Shi A., Li X. The asymmetric synthesis of (R,R)-formoterol via transfer hydrogenation with polyethylene glycol bound Rh catalyst in PEG2000 and water. Chirality. 2010;22:206–211. PubMed

Zhu Y., Stubbs L.P., Ho F., Liu R., Ship C.P., Maguire J.A., Hosmane N.S. Magnetic nanocomposites: A new perspective in catalysis. ChemCatChem. 2010;2:365–374. doi: 10.1002/cctc.200900314. DOI

Schätz A., Reiser O., Stark W.J. Nanoparticles as semi-heterogeneous catalyst supports. Chem. Eur. J. 2010;16:8950–8967. doi: 10.1002/chem.200903462. PubMed DOI

Ranganath K.V.S., Glorius F. Superparamagnetic nanoparticles for asymmetric catalysis-a perfect match. Catal. Sci. Technol. 2011;1:13–22. doi: 10.1039/c0cy00069h. DOI

Polshettiwar V., Luque R., Fihri A., Zhu H., Bouhrara M., Basset J.-M. Magnetically Recoverable Nanocatalysts. Chem. Rev. 2011 doi: 10.1021/cr100230z. in press. PubMed DOI

Kassube J., Gade L. Stereoselective Dendrimer Catalysis. In: Gade L., editor. Dendrimer Catalysis. Volume 20. Springer; Berlin/Heidelberg, Germany: 2006. pp. 61–96.

Méry D., Astruc D. Dendritic catalysis: Major concepts and recent progress. Coord. Chem. Rev. 2006;250:1965–1979. doi: 10.1016/j.ccr.2005.11.012. DOI

de Jesús E., Flores J.C. Dendrimers: Solutions for catalyst separation and recycling – a review. Ind. Eng. Chem. Res. 2008;47:7968–7981. doi: 10.1021/ie800381d. DOI

Dijkstra H.P., van Klink G.P.M., van Koten G. The use of ultra- and nanofiltration techniques in homogeneous catalyst recycling. Acc. Chem. Res. 2002;35:798–810. doi: 10.1021/ar0100778. PubMed DOI

Chen Y.-C., Wu T.-F., Deng J.-G., Liu H., Jiang Y.-Z., Choi M.C.K., Chan A.S.C. Dendritic catalysts for asymmetric transferhydrogenation. Chem. Commun. 2001:1488–1489. doi: 10.1039/b104160f. DOI

Hawker C.J., Frechet J.M.J. Preparation of polymers with controlled molecular architecture. A new convergent approach to dendritic macromolecules. J. Am. Chem. Soc. 1990;112:7638–7647. doi: 10.1021/ja00177a027. DOI

Newkome G.R., Lin X. Symmetrical, four-directional, poly(ether-amide) cascade polymers. Macromolecules. 1991;24:1443–1444. doi: 10.1021/ma00006a042. DOI

Chen Y.-C., Wu T.-F., Jiang L., Deng J.-G., Liu H., Zhu J., Jiang Y.-Z. Synthesis of dendritic catalysts and application in asymmetric transfer hydrogenation. J. Org. Chem. 2005;70:1006–1010. doi: 10.1021/jo048317v. PubMed DOI

Liu W., Cui X., Cun L., Zhu J., Deng J. Tunable dendritic ligands of chiral 1,2-diamine and their application in asymmetric transfer hydrogenation. Tetrahedron Asymmetry. 2005;16:2525–2530. doi: 10.1016/j.tetasy.2005.07.008. DOI

Gaikwad A.V., Boffa V., Ten Elshof J.E., Rothenberg G. Cat-in-a-cup: Facile separation of large homogeneous catalysts. Angew. Chem. Int. Ed. 2008;47:5407–5410. doi: 10.1002/anie.200801116. PubMed DOI

Wang W., Wang Q. A fluorinated dendritic TsDPEN-Ru(II) catalyst for asymmetric transfer hydrogenation of prochiral ketones in aqueous media. Chem. Commun. 2010;46:4616–4618. doi: 10.1039/c002168g. PubMed DOI

Geldbach T.J., Dyson P.J. A versatile ruthenium precursor for biphasic catalysis and its application in ionic liquid biphasic transfer hydrogenation: Conventional vs. task-specific catalysts. J. Am. Chem. Soc. 2004;126:8114–8115. doi: 10.1021/ja048886k. PubMed DOI

Letondor C., Ward T.R. Artificial metalloenzymes for enantioselective catalysis: Recent advances. ChemBioChem. 2006;7:1845–1852. doi: 10.1002/cbic.200600264. PubMed DOI

Steinreiber J., Ward T.R. Artificial metalloenzymes as selective catalysts in aqueous media. Coord. Chem. Rev. 2008;252:751–766. doi: 10.1016/j.ccr.2007.09.016. DOI

Rosati F., Roelfes G. Artificial metalloenzymes. ChemCatChem. 2010;2:916–927. doi: 10.1002/cctc.201000011. DOI

Letondor C., Humbert N., Ward T.R. Artificial metalloenzymes based on biotin-avidin technology for the enantioselective reduction of ketones by transfer hydrogenation. Proc. Natl. Acad. Sci. USA. 2005;102:4683–4687. doi: 10.1073/pnas.0409684102. PubMed DOI PMC

Letondor C., Pordea A., Humbert N., Ivanova A., Mazurek S., Novic M., Ward T.R. Artificial transfer hydrogenases based on the biotin-(strept)avidin technology: Fine tuning the selectivity by saturation mutagenesis of the host protein. J. Am. Chem. Soc. 2006;128:8320–8328. doi: 10.1021/ja061580o. PubMed DOI

Creus M., Pordea A., Rossel T., Sardo A., Letondor C., Ivanova A., LeTrong I., Stenkamp R.E., Ward T.R. X-Ray structure and designed evolution of an artificial transfer hydrogenase. Angew. Chem. Int. Ed. 2008;47:1400–1404. doi: 10.1002/anie.200704865. PubMed DOI

Ward T.R. Artificial metalloenzymes based on the biotin-avidin technology: Enantioselective catalysis and beyond. Acc. Chem. Res. 2010;44:47–57. doi: 10.1021/ar100099u. PubMed DOI

Dürrenberger M., Heinisch T., Wilson Y.M., Rossel T., Nogueira E., Knörr L., Mutschler A., Kersten K., Zimbron M.J., Pierron J., et al. Artificial transfer hydrogenases for the enantioselective reduction of cyclic imines. Angew. Chem. Int. Ed. 2011;50:3026–3029. doi: 10.1002/anie.201007820. PubMed DOI

Polborn K., Severin K. Biomimetic catalysis with immobilised organometallic Ruthenium complexes: Substrate- and regioselective transfer hydrogenation of ketones. Chem. Eur. J. 2000;6:4604–4611. doi: 10.1002/1521-3765(20001215)6:24<4604::AID-CHEM4604>3.0.CO;2-Y. PubMed DOI

Locatelli F., Gamez P., Lemaire M. Molecular imprinting of polymerised catalytic complexes in asymmetric catalysis. J. Mol. Catal., A Chem. 1998;135:89–98. doi: 10.1016/S1381-1169(97)00288-4. DOI

Weng Z., Muratsugu S., Ishiguro N., Ohkoshi S.-i., Tada M. Preparation of surface molecularly imprinted Ru-complex catalysts for asymmetric transfer hydrogenation in water media. Dalton Trans. 2011;40:2338–2347. doi: 10.1039/C0DT00950D. PubMed DOI

Yamakawa M., Ito H., Noyori R. The metal-ligand bifunctional catalysis: A theoretical study on the Ruthenium(II)-catalyzed hydrogen transfer between alcohols and carbonyl compounds. J. Am. Chem. Soc. 2000;122:1466–1478. doi: 10.1021/ja991638h. DOI

Ikariya T., Blacker A.J. Asymmetric transfer hydrogenation of ketones with bifunctional transition metal-based molecular catalysts. Acc. Chem. Res. 2007;40:1300–1308. doi: 10.1021/ar700134q. PubMed DOI

Koike T., Ikariya T. Mechanistic aspects of formation of chiral Ruthenium hydride complexes from 16-electron ruthenium amide complexes and formic acid: Facile reversible decarboxylation and carboxylation. Adv. Synth. Catal. 2004;346:37–41. doi: 10.1002/adsc.200303152. DOI

Kuzma M., Pelantová H., Sedmera P., Kačer P., Šiklová H., Červený L. Study on Influence of Amines on Behavior of the Noyoris Catalysts Under Transfer Hydrogenation Conditions Studied by NMR. In: Somorjai G., editor. International Symposium on Relations between Homogeneous and Heterogeneous Catalysis XIII (ISHHC XIII) University of California; Berkeley, CA, USA: 2007.

Wu X., Liu J., di Tommaso D., Iggo J.A., Catlow C.R.A., Bacsa J., Xiao J. A multilateral mechanistic study into asymmetric transfer hydrogenation in water. Chem. Eur. J. 2008;14:7699–7715. doi: 10.1002/chem.200800559. PubMed DOI

Åberg J.B., Samec J.S.M., Backvall J.-E. Mechanistic investigation on the hydrogenation of imines by [p-(Me2CH)C6H4Me]RuH(NH2CHPhCHPhNSO2C6H4-p-CH). Experimental support for an ionic pathway. Chem. Commun. 2006:2771–2773. doi: 10.1039/B605838H. PubMed DOI

Balcells D., Maseras F. Computational approaches to asymmetric synthesis. New J. Chem. 2007;31:333–343. doi: 10.1039/b615528f. DOI

Václavík J., Kuzma M., Přech J., Kačer P. Asymmetric transfer hydrogenation of imines and ketones using chiral Ru(II)Cl(η6-p-cymene)[(S,S)-N-TsDPEN] as a catalyst: A computational study. Organometallics. 2011 submitted.

Lee C., Yang W., Parr R.G. Development of the Colle-Salvetti correlation-energy formula into a functional of the electron density. Phys. Rev. B. 1988;37:785. doi: 10.1103/PhysRevB.37.785. PubMed DOI

Becke A.D. Density-functional thermochemistry III. The role of exact exchange. J. Chem. Phys. 1993;98:5648–5652. doi: 10.1063/1.464913. DOI

Hay P.J., Wadt W.R. Ab initio effective core potentials for molecular calculations. Potentials for the transition metal atoms Sc to Hg. J. Chem. Phys. 1985;82:270–283. doi: 10.1063/1.448799. DOI

Experimental and theoretical perspectives of the Noyori-Ikariya asymmetric transfer hydrogenation of imines

Practical aspects and mechanism of asymmetric hydrogenation with chiral half-sandwich complexes