Developing chiral ligands for asymmetric hydrogenation

Accounts of Chemical Research

Volumn 40, Issue 12, 2007, Pages 1278-1290

  Zhang, Weicheng ^a   Chi, Yongxiang ^a   Zhang, Xumu ^a  

^a PENNSYLVANIA STATE UNIVERSITY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

2,3 O ISOPROPYLIDENE 2,3 DIHYDROXYL 1,4 BIS(DIPHENYLPHOSPHINO)BUTANE; 2,3- O-ISOPROPYLIDENE-2,3-DIHYDROXYL-1,4-BIS(DIPHENYLPHOSPHINO)BUTANE; BUTANE; LIGAND; PHOSPHINE; PHOSPHINE DERIVATIVE; RHODIUM; UNCLASSIFIED DRUG;

CHEMISTRY; HYDROGENATION; REVIEW; STEREOISOMERISM;

BUTANES; HYDROGENATION; LIGANDS; PHOSPHINES; RHODIUM; STEREOISOMERISM;

EID: 38049077372     PISSN: 00014842     EISSN: None     Source Type: Journal    
DOI: 10.1021/ar7000028     Document Type: Review

References (95)

1. (a) Asymmetric Catalysis in Organic Synthesis; Noyori, R., Ed.; Wiley: New York, 1994.
2. (b) Comprehensive Asymmetric Catalysis; Jacobsen, E. N., Pfaltz, A., Yamamoto, H., Eds.; Springer: Berlin, Germany, 1999; Vol. 1-3.
3. (c) Catalytic Asymmetric Synthesis; Ojima, I., Ed.; Wiley-VCH: New York, 2000.
4. (d) Tang, W.; Zhang, X. New Chiral Phosphorus Ligands for Enantioselective Hydrogenation. Chem. Rev. 2003, 103, 3029-3069.
5. (a) Knowles, W. S.; Sabacky, M. J. Catalytic Asymmetric Hydrogenation Employing a Soluble, Optically Active, Rhodium Complex. Chem. Commun. 1968, 1445-1446.
6. (b) Horner, L.; Siegel, H.; Buthe, H. Asymmetric Catalytic Hydrogenation with an Optically Active Phosphinerhodium Complex in Homogeneous Solution. Angew. Chem., Int. Ed. 1968, 7, 942.
7. 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(diphenylphosphinolbutane, a New Chiral Diphosphine. J. Am. Chem. Soc. 1972, 94, 6429-6433.
8. (a) Vineyard, B. D.; Knowles, W. S.; Sabacky, M. J.; Bachman, G. L.; Weinkauff, O. J. Asymmetric Hydrogenation. Rhodium Chiral Bisphosphine Catalyst. J. Am. Chem. Soc. 1977, 99, 5946-5952.
9. (b) Knowles, W. S. Asymmetric Hydrogenation. Acc. Chem. Res. 1983, 16, 106-112.
10. (c) Knowles, W. S. Asymmetric Hydrogenations (Nobel Lecture). Angew. Chem., Int. Ed. 2002, 41, 1998-2007.
11. (a) Miyashita, A.; Yasuda, A.; Takaya, H.; Toriumi, K.; Ito, T.; Souchi, T.; Noyori, R. Synthesis of 2,2′-Bis(diphenylphosphino)-1,1′- binaphthyl (BINAP), an Atropisomeric Chiral Bis(triaryl)phosphine, and Its Use in the Rhodium(I)-Catalyzed Asymmetric Hydrogenation of α-(Acylamino) acrylic Acids. J. Am. Chem. Soc. 1980, 102, 7932-7934.
12. (b) Noyori, R.; Ohkuma, T. Asymmetric Catalysis by Architectural and Functional Molecular Engineering: Practical Chemo- and Stereoselective Hydrogenation of Ketones. Angew. Chem., Int. Ed. 2001, 40, 40-73.
13. (c) Noyori, R. Asymmetric Catalysis: Science and Opportunities (Nobel Lecture). Angew. Chem., Int. Ed. 2002, 41, 2008-2022.
14. 2-Symmetric Bis(phospholanes) and Their Use in Highly Enantioselective Hydrogenation Reactions. J. Am. Chem. Soc. 1991, 113, 8518-8519.
15. 2-Symmetric Bis(phospholanes): Production of α-Amino Acid Derivatives via Highly Enantioselective Hydrogenation Reactions. J. Am. Chem. Soc. 1993, 115, 10125-10138.
16. (c) Burk, M. J. Modular Phospholane Ligands in Asymmetric Catalysis. Acc. Chem. Res. 2000, 33, 363-372.
17. (a) Togni, A.; Breutel, C.; Schnyder, A.; Spindler, F.; Landert, H.; Tijani, A. A Novel Easily Accessible Chiral Ferrocenyldiphosphine for Highly Enantioselective Hydrogenation, Allylic Alkylation, and Hydroboration Reactions. J. Am. Chem. Soc. 1994, 116, 4062-4066.
18. (b) Blaser, H.-U.; Brieden, W.; Pugin, B.; Spindler, F.; Studer, M.; Togni, A. Solvias Josiphos Ligands: From Discovery to Technical Applications. Top. Catal. 2002, 19, 3-16.
19. (a) Helmchen, G.; Pfaltz, A. Phosphinooxazolines - A New Class of Versatile, Modular P,N-Ligands for Asymmetric Catalysis. Acc. Chem. Res. 2000, 33, 336-345.
20. 2-symmetric P,P- and N,N-Ligands to Sterically and Electronically Nonsymmetrical P,N-Ligands. Proc Natl. Acad. Sci. U.S.A. 2004, 101, 5723-5726.
21. (c) Bell, S.; Wustenberg, B.; Kaiser, S.; Menges, F.; Netscher, T.; Ffaltz, A. Asymmetric Hydrogenation of Unfunctionalized, Purely Alkyl-Substituted Olefins. Science 2006, 311, 642-644.
22. (a) Claver, C.; Fernandez, E.; Gillon, A.; Heslop, K.; Hyett, D. J.; Martorell, A.; Orpen, A. G.; Pringle, P. G. Biarylphosphonites: a Class of Monodentate Phosphorus(III) Ligands that Outperform Their Chelating Analogues in Asymmetric Hydrogenation Catalysis. Chem. Commun. 2000, 961-962.
23. (b) Reetz, M. T.; Mehler, G. Highly Enantioselective Rh-Catalyzed Hydrogenation Reactions Based on Chiral Monophosphite Ligands. Angew. Chem., Int. Ed. 2000, 39, 3889-3890.
24. (c) van den Berg, M.; Minnaard, A. J.; Schudde, E. P.; van Esch, J.; de Vries, A. H. M.; de Vries, J. G.; Feringa, B. L. Highly Enantioselective Rhodium-Catalyzed Hydrogenation with Monodentate Ligands. J. Am. Chem. Soc. 2000, 122, 11539-11540.
25. (a) Tang, W.; Zhang, X. A Chiral 1,2-Bisphospholane Ligand with a Novel Structural Motif: Applications in Highly Enantioselective Rh-Catalyzed Hydrogenations. Angew. Chem., Int. Ed. 2002, 41, 1612-1614.
26. (b) Tang, W.; Zhang, X. Highly Efficient Synthesis of Chiral β-Amino Acid Derivatives via Asymmetric Hydrogenation. Org. Lett. 2002, 4, 4159-4161.
27. (c) Tang, W.; Liu, D.; Zhang, X. Asymmetric Hydrogenation of Itaconic Acid and Enol Acetate Derivatives with the Rh-TangPhos Catalyst. Org. Lett. 2003, 5, 205-207.
28. (d) Dai, Q.; Yang, W.; Zhang, X. Efficient Rhodium-Catalyzed Asymmetric Hydrogenation for the Synthesis of a New Class of N-Aryl β-Amino Acid Derivatives. Org. Lett. 2005, 7, 5343-5345.
29. (e) Yang, Q.; Gao, W.; Deng, J.; Zhang, X. Highly Enantioselective Hydrogenation of N-Phthaloyl Enamides. Tetrahedron Lett. 2006, 47, 821-823.
30. (f) Wang, C.; Tao, H.; Zhang, X. Highly Enantioselective Ru-Catalyzed Hydrogenation of β-Keto Esters Using Electron-Donating Bis(trialkylphosphine) Ligand-TangPhos. Tetrahedron Lett. 2006, 47, 1901-1903.
31. (g) Yang, Q.; Shang, G.; Gao, W.; Deng, J.; Zhang, X. A Highly Enantioselective, Pd-TangPhos-Catalyzed Hydrogenation of N-Tosylimines. Angew. Chem., Int. Ed. 2006, 45, 3832-3835.
32. (h) Shang, G.; Yang, Q.; Zhang, X. Rh-Catalyzed Asymmetric Hydrogenation of α-Aryl Imino Esters: An Efficient Enantioselective Synthesis of Aryl Glycine Derivatives. Angew. Chem., Int. Ed. 2006, 45, 6360-6362.
33. (i) Lei, A.; Chen, M.; He, M.; Zhang, X. Asymmetric Hydrogenation of Pyridines: Enantioselective Synthesis of Nipecotic Acid Derivatives. Eur. J. Org. Chem. 2006, 4343-4347.
34. (a) Liu, D.; Zhang, X. Practical P-Chiral Phosphane Ligand for Rh-Catalyzed Asymmetric Hydrogenation. Eur. J. Org. Chem. 2005, 646-649.
35. (b) Liu, D.; Gao, W.; Wang, C.; Zhang, X. Practical Synthesis of Enantiopure γ-Amino Alcohols by Rhodium-Catalyzed Asymmetric Hydrogenation of β-Secondary-Amino Ketones. Angew. Chem., Int. Ed. 2005, 44, 1687-1689.
36. (c) Sun, X.; Zhou, L.; Wang, C.-J.; Zhang, X. Rh-Catalyzed Highly Enantioselective Synthesis of β-Methylcinnamic Acids. Angew. Chem., Int. Ed. 2007, 46, 2623-2626.
37. Tang, W.; Wang, W.; Zhang, X. Phospholane-Oxazoline Ligands for Ir-Catalyzed Asymmetric Hydrogenation. Angew. Chem., Int. Ed. 2003, 42, 943-946.
38. (a) Jiang, Q.; Jiang, Y.; Xiao, D.; Cao, P.; Zhang, X. High Enantioselective Hydrogenation of Simple Ketones Catalyzed by a Rh-PennPhos Complex. Angew. Chem., Int. Ed. 1998, 37, 1100-1103.
39. (b) Zhang, Z.; Zhu, G.; Jiang, Q.; Xiao, D.; Zhang, X. Highly Enantioselective Hydrogenation of Cyclic Enamides Catalyzed by a Rh-PennPhos Catalyst. J. Org. Chem. 1999, 64, 1774-1775.
40. (c) Jiang, Q.; Xiao, D.; Zhang, Z.; Cao, P.; Zhang, X. Highly Enantioselective Hydrogenation of Cyclic Enol Acetates Catalyzed by a Rh-PennPhos Complex. Angew. Chem., Int. Ed. 1999, 38, 516-518.
41. (a) Li, W.; Zhang, Z.; Xiao, D.; Zhang, X. Rhodium-Hydroxyl Bisphospholane Catalyzed Highly Enantioselective Hydrogenation of Dehydroamino Acids and Esters. Tetrahedron Lett. 1999, 40, 6701-6704.
42. (b) Li, W.; Zhang, Z.; Xiao, D.; Zhang, X. Synthesis of Chiral Hydroxyl Phospholanes from D-Mannitol and Their Use in Asymmetric Catalytic Reactions. J. Org. Chem. 2000, 65, 3489-3496.
43. (c) Dai, Q.; Wang, C.; Zhang, X. Chiral Bisphospholane Ligands (Meketalphos): Synthesis of their Rh(I) Complexes and Applications in Asymmetric Hydrogenation. Tetrahedron 2006, 62, 868-871.
44. Parallel to our work, other groups also carried out independent studies on D-mannitol-derived bisphospholane ligands, see (a) Carmichael, D.; Doucet, H.; Brown, J. M. Hybrid P-Chiral Diphosphines for Asymmetric Hydrogenation. Chem. Commun. 1999, 261-262.
45. (b) Holz, J.; Quirmbach, M.; Schmidt, U.; Heller, D.; Stürmer, R.; Börner, A. Synthesis of a New Class of Functionalized Chiral Bisphospholane Ligands and the Application in Enantioselective Hydrogenations. J. Org. Chem. 1998, 63, 8031-8034.
46. (c) Holz, J.; Heller, D.; Stürmer, R.; Börner, A. Synthesis of the First Water-Soluble Chiral Tetrahydroxy Diphosphine Rh(I) Catalyst for Enantioselective Hydrogenation. Tetrahedron Lett. 1999, 40, 7059-7062.
47. (d) Yan, Y.-Y.; Rajanbabu, T. V. Ligand Tuning in Asymmetric Catalysis: Mono- and Bis-phospholanes for a Prototypical Pd-Catalyzed Asymmetric Allylation Reaction. Org. Lett. 2000, 2, 199-202.
48. (e) Yan, Y.-Y.; Rajanbabu, T. V. Highly Flexible Synthetic Routes to Functionalized Phospholanes from Carbohydrates. J. Org. Chem. 2000, 65, 900-906.
49. Liu, D.; Li, W.; Zhang, X. A Novel Chiral Ferrocenyl Phosphine Ligand from Sugar: Applications in Rh-Catalyzed Asymmetric Hydrogenation Reactions. Org. Lett. 2002, 4, 4471-4474.
50. Yan, Y.; Zhang, X. Six-Membered Bis(azaphosphorinane), Readily Available Ligand for Highly Enantioselective Asymmetric Hydrogenations. Tetrahedron Lett. 2006, 47, 1567-1569.
51. Xiao, D.; Zhang, Z.; Zhang, X. Synthesis of a Novel Chiral Binaphthyl Phospholane and Its Application in the Highly Enantioselective Hydrogenation of Enamides. Org. Lett. 1999, 1, 1679-1681.
52. (a) Xiao, D.; Zhang, X. Highly Enantioselective Hydrogenation of Acyclic Imines Catalyzed by Ir-f-Binaphane Complexes. Angew. Chem., Int. Ed. 2001, 40, 3425-3428.
53. (b) Chi, Y.; Zhou, Y.-G.; Zhang, X. Highly Enantioselective Reductive Amination of Simple Aryl Ketones Catalyzed by Ir-f-Binaphane in the Presence of Titanium(IV) Isopropoxide and Iodine. J. Org. Chem. 2003, 68, 4120-4122.
54. Tang, W.; Wang, W.; Chi, Y.; Zhang, X. A Bisphosphepin Ligand with Stereogenic Phosphorus Centers for the Practical Synthesis of β-Aryl-β-amino Acids by Asymmetric Hydrogenation. Angew. Chem., Int. Ed. 2003, 42, 3509-3511.
55. Gladiali, S.; Dore, A.; Fabbri, D.; De Lucchi, O.; Manassero, M. Novel Atropisomeric Phosphorus Ligands: 4,5-Dihydro-3H-dinaphtho[2,1-c;1′,2′-eiphosphepine Derivatives. Tetrahedron: Asymmetry 1994, 5, 511-514.
56. (a) Zhu, G.; Chen, Z.; Jiang, Q.; Xiao, D.; Cao, P.; Zhang, X. Asymmetric [3 + 2] Cycloaddition of 2,3-Butadienoates with Electron-Deficient Olefins Catalyzed by Novel Chiral 2,5-Dialkyl-7-phenyl-7-phosphabicyclo[2.2.1]heptanes. J. Am. Chem. Soc. 1997, 119, 3836-3837.
57. (b) Chen, Z.; Jiang, Q.; Zhu, G.; Xiao, D.; Cao, P.; Guo, C.; Zhang, X. Syntheses of Novel Chiral Monophosphines, 2,5-Dialkyl-7-phenyl-7-phosphabicyclo- [2.2.1]heptanes, and Their Application in Highly Enantioselective Pd-Catalyzed Allylic Alkylations. J. Org. Chem. 1997, 62, 4521-4523.
58. (a) Imamoto, T.; Watanabe, J.; Wada, Y.; Masuda, H.; Yamada, H.; Tsuruta, H.; Matsukawa, S.; Yamaguchi, K. P-Chiral Bis(trialkylphosphine) Ligands and Their Use in Highly Enantioselective Hydrogenation Reactions. J. Am. Chem. Soc. 1998, 120, 1635-1636.
59. (b) Yamanoi, Y.; Imamoto, T. Methylene-Bridged P-Chiral Diphosphines in Highly Enantioselective Reactions. J. Org. Chem. 1999, 64, 2988-2989.
60. (a) Huang, J.; Bunel, E.; Allgeier, A.; Tedrow, J.; Storz, T.; Preston, J.; Correll, T.; Manley, D.; Soukup, T.; Jensen, R.; Syed, R.; Moniz, G.; Larsen, R.; Martinelli, M.; Reider, P. J. A Highly Enantioselective Catalyst for Asymmetric Hydroformylation of [2.2.1]-Bicyclic Olefins. Tetrahedron Lett. 2005, 46, 7831-7834.
61. (b) Axtell, A. T.; Klosin, J.; Abboud, K. A. Evaluation of Asymmetric Hydrogenation Ligands in Asymmetric Hydroformylation Reactions. Highly Enantioselective Ligands Based on Bis-phosphacycles. Organometallics 2006, 25, 5003-5009.
62. (a) Hoge, G. Technology Development at Pfizer: "Real World" Asymmetric Hydrogenation. Conference: Modern Synthetic Methods, Reaction to Reality and Chiral USA 2005. July 12-14, 2005, Princeton, NJ.
63. (b) Conway, B. G.; Nanninga, T. N.; Wu, H.; Hoge, G.; Pearlman, B. A.; Winkle, D. D. Preparation of β-Amino Acids Having Affinity for the α-2-δ Protein. PCT Int. Appl. 2006, WO 2006008612.
64. (a) Zhang, Z.; Qian, H.; Longmire, J.; Zhang, X. Synthesis of Chiral Bisphosphines with Tunable Bite Angles and Their Applications in Asymmetric Hydrogenation of β-Ketoesters. J. Org. Chem. 2000, 65, 6223-6226.
65. (b) Wu, S.; Wang, W.; Tang, W.; Lin, M.; Zhang, X. Highly Enantioselective Hydrogenation of Enol Acetates Catalyzed by Ru-TunaPhos Complexes. Org. Lett. 2002, 4, 4495-4497.
66. (c) Tang, W.; Wu, S.; Zhang, X. Enantioselective Hydrogenation of Tetrasubstituted Olefins of Cyclic β-(Acylamino)acrylates. J. Am. Chem. Soc. 2003, 125, 9570-9571.
67. (d) Lei, A.; Wu, S.; He, M.; Zhang, X. Highly Enantioselective Asymmetric Hydrogenation of α-Ph-thalimide Ketone: An Efficient Entry to Enantiomerically Pure Amino Alcohols. J. Am. Chem. Soc. 2004, 126, 1626-1627.
68. (e) Wang, C.; Sun, X.; Zhang, X. Enantioselective Hydrogenation of Allylphthalimides: An Efficient Method for the Synthesis of β-Methyl Chiral Amines. Angew. Chem., Int. Ed. 2005, 44, 4933-4935.
69. (f) Wang, C.; Sun, X.; Zhang, X. Highly Enantioselective Hydrogenation of α-Keto Esters Catalyzed by Ru-Tunephos Complexes. Synlett 2006, 1169-1172.
70. (a) Zhou, Y.-G.; Tang, W.; Wang, W.-B.; Li, W.; Zhang, X. Highly Effective Chiral ortrio-Substituted BINAPO Ligands (o-BINAPO): Applications in Ru-Catalyzed Asymmetric Hydrogenations of β-Aryl- Substituted β-(Acylamino)acrylates and β-Keto Esters. J. Am. Chem. Soc. 2002, 124, 4952-4953.
71. (b) Zhou, Y.-G.; Zhang, X. Synthesis of Novel BINOL-Derived Chiral Bisphosphorus Ligands and Their Applications in Catalytic Asymmetric Hydrogenation. Chem. Commun. 2002, 1124-1125.
72. Tang, W.; Chi, Y.; Zhang, X. An ortho-Substituted BIPHEP Ligand and Its Applications in Rh-Catalyzed Hydrogenation of Cyclic Enamides. Org. Lett. 2002, 4, 1695-1698.
73. Yan, Y.; Chi, Y.; Zhang, X. Novel Phosphine-Phosphite and Phosphine-Phosphinite Ligands for Highly Enantioselective Asymmetric Hydrogenation. Tetrahedron: Asymmetry 2004, 15, 2173-2175.
74. Wu, S.; He, M.; Zhang, X. Synthesis of ortho-Phenyl Substituted MeO-BIPHEP Ligand and its Application in Rh-Catalyzed Asymmetric Hydrogenation. Tetrahedron: Asymmetry 2004, 15, 2177-2180.
75. (a) Zhang, W.; Zhang, X. Synthesis of Triphosphorous Bidentate Phosphine-Phosphoramidite Ligands: Application in the Highly Enantioselective Hydrogenation of ortho-Substituted Aryl Enamides. Angew. Chem., Int. Ed. 2006, 45, 5515-5518.
76. (b) Zhang, W.; Zhang, X. Highly Enantioselective Hydrogenation of α-Dehydroamino Esters and ltaconates with Triphosphorous Bidentate Ligands and the Unprecedented Solvent Effect thereof. J. Org. Chem. 2007, 72, 1020-1023.
77. Shimizu, H.; Nagasaki, I.; Saito, T. Recent Advances in Biaryl-Type Bisphosphine Ligands. Tetrahedron 2005, 61, 5405-5432.
78. Komarov, I. V.; Borner, A. Highly Enantioselective or Not? - Chiral Monodentate Monophosphorus Ligands in the Asymmetric Hydrogenation. Angew. Chem., Int. Ed. 2001, 40, 1197-1200.
79. Hoen, R.; Boogers, J. A. F.; Bernsmann, H.; Minnaard, A. J.; Meetsma, A.; Tiemersma-Wegman, T. D.; de Vries, A. H. M.; de Vries, J. G.; Feringa, B. L. Achiral Ligands Dramatically Enhance Rate and Enantioselectivity in the Rh/Phosphoramidite-Catalyzed Hydrogenation of α,β-Disubstituted Unsaturated Acids. Angew. Chem., Int. Ed. 2005, 44, 4209-4212.
80. Inoguchi, K.; Sakuraba, S.; Achiwa, K. Design Concepts for Developing Highly Efficient Chiral Bisphosphine Ligands in Rhodium-Catalyzed Asymmetric Hydrogenations. Synlett 1992, 169-178.
81. (a) Gridnev, I. D.; Higashi, N.; Asakura, K.; Imamoto, T. Mechanism of Asymmetric Hydrogenation Catalyzed by a Rhodium Complex of (S,S)-1,2- Bis(tert-butylmethylphosphino)ethane. Dihydride Mechanism of Asymmetric Hydrogenation. J. Am. Chem. Soc. 2000, 122, 7183-7194.
82. (b) Gridnev, I. D.; Yasutake, M.; Higashi, N.; Imamoto, T. Asymmetric Hydrogenation of Enamides with Rh-BisP* and Rh-MiniPHOS Catalysts. Scope, Limitations, and Mechanism. J. Am. Chem. Soc. 2001, 123, 5268-5276.
83. (c) Gridnev, I. D.; Imamoto, T. On the Mechanism of Stereoselection in Rh-Catalyzed Asymmetric Hydrogenation: A General Approach for Predicting the Sense of Enantioselectivity. Acc. Chem. Res. 2004, 37, 633-644.
84. van Wagenen, B. C.; Moe, S. T.; Balandrin, M. F.; DelMar, E. G.; Nemeth, E. F. Calcium Receptor-Active Compounds. U.S. Patent 2001, 6,211,244.
85. Kagan, H. B.; Fiaud, J. C.; Hoornaert, C.; Meyer, D.; Poulin, J. C. Synthesis of New Chiral Phosphines for Asymmetric Catalysis. Bull. Soc. Chim. Belg. 1979, 88, 923-931.
86. Li, W.; Zhang, X. Synthesis of 3,4-O-Isopropylidene-(3S, 4S)-dihydroxy-(2R,5R)-bis(diphenylphosphino)hexane and its Application in Rh-Catalyzed Highly Enantioselective Hydrogenation of Enamides. J. Org. Chem. 2000, 65, 5871-5874.
87. (a) Zhu, G.; Cao, P.; Jiang, Q.; Zhang, X. High Enantioselective Rh-Catalyzed Hydrogenations with a New Chiral 1,4-Bisphosphine Containing a Cyclic Backbone. J. Am. Chem. Soc. 1997, 119, 1799-1800.
88. (b) Zhu, G.; Zhang, X. Asymmetric Rh-Catalyzed Hydrogenation of Enamides with a Chiral 1,4-Bisphosphine Bearing Diphenyl-phosphino Groups. J. Org. Chem. 1998, 63, 9590-9593.
89. (c) Zhu, G.; Casalnuovo, A. L.; Zhang, X. Practical Syntheses of β-Amino Alcohols via Asymmetric Catalytic Hydrogenation. J. Org. Chem. 1998, 63, 8100-8101.
90. (d) Zhu, G.; Zhang, X. Additive Effects in Ir-BICP Catalyzed Asymmetric Hydrogenation of Imines. Tetrahedron: Asymmetry 1998, 9, 2415-2418.
91. (e) Zhu, G.; Chen, Z.; Zhang, X. Highly Efficient Asymmetric Synthesis of β-Amino Acid Derivatives via Rhodium-Catalyzed Hydrogenation of β-(Acylamino)Acrylates. J. Org. Chem. 1999, 64, 6907-6910.
92. (f) Cao, P.; Zhang, X. Ru-BICP-Catalyzed Asymmetric Hydrogenation of Aromatic Ketones. J. Org. Chem. 1999, 64, 2127-2129.
93. Zhang, X. Developing a Chiral Toolbox for Asymmetric Catalytic Reactions. Enantiomer 1999, 4, 541-555.
94. Blaser, H.-U. The Chiral Switch of (S)-Metolachlor: A Personal Account of an Industrial Odyssey in Asymmetric Catalysis. Adv. Synth. Catal. 2002, 344, 17-31.
95. Baumann, K. L.; Butler, D. E.; Deering, C. F.; Mennen, K. E.; Millar, A.; Nanninga, T. N.; Palmer, C. W.; Roth, B. D. The Convergent Synthesis of CI-981, an Optically Active, Highly Potent, Tissue Selective Inhibitor of HMG-CoA Reductase. Tetrahedron Lett. 1992, 33, 2283-2284.