Bidentate Camphane Phosphine Phosphinites as Ligands in Asymmetric Hydrogenation of α-Dehydroamino Acids

Abstract

The rhodium(I) catalyzed asymmetric hydrogenation of methyl (Z)-N-acetamido cinnamates 5a-c in the presence of camphor-derived phosphine phosphinites 4a-c gave the corresponding phenyl alanine derivatives 6a-c with good enantioselectivities (up to 89% ee) and high conversions.

Key words

hydrogenation - rhodium - asymmetric synthesis - amino acids - phosphines

References

• Reviews:
• 1a Rossen K. Angew. Chem. Int. Ed.  2001,  40:  4611 ; Angew. Chem. 2001, 113, 4747
• 1b Brown JM. In Comprehensive Asymmetric Catalysis   Vol. 1:  Jacobsen EN. Pfaltz A. Yamamoto H. Springer Verlag; New York: 1999.  p.1 
• 2a Pàmiez O. Diéguez M. Net G. Ruiz A. Claver C. J. Org. Chem.  2001,  66:  8364 
• 2b Deerenburg S. Pàmiez O. Diéguez M. Claver C. Kamer PCJ. van Leeuwen PWNM. J. Org. Chem.  2001,  66:  7626 
• 2c Pàmiez O. Diéguez M. Net G. Ruiz A. Claver C. Chem. Commun.  2000,  2383 
• 3 Review: Agbossou F. Carpentier J.-F. Hapiot F. Suisse I. Mortreux A. Coord. Chem. Rev.  1998,  178-180:  1615 
• 4a Xie Y. Lou R. Li Z. Mi A. Jiang Y. Tetrahedron: Asymmetry  2000,  11:  1487 
• 4b Li X. Lou R. Yeung C.-H. Chan ASC. Wong WK. Tetrahedron: Asymmetry  2000,  11:  2077 
• 4c Mi A. Lou R. Jiang Y. Deng J. Qin Y. Fu F. Li Z. Hu W. Chan ASC. Synlett  1998,  847 
• 4d Komarov IV. Gorichko MV. Kornilov MY. Tetrahedron: Asymmetry  1997,  8:  435 
• 4e Kreuzfeld HJ. Schmidt U. Döbler C. Krause HW. Tetrahedron: Asymmetry  1996,  7:  1011 
• 4f Döbler C. Schmidt U. Krause HW. Kreuzfeld HJ. Michalik M. Tetrahedron: Asymmetry  1995,  6:  384 
• 4g Krause HW. Kreuzfeld HJ. Döbler C. Tetrahedron: Asymmetry  1992,  3:  555 
• 4h Döbler C. Kreuzfeld HJ. Pracejus H. J. Organomet. Chem.  1988,  344:  89 
• 4i Karim A. Mortreux A. Petit F. J. Organomet. Chem.  1986,  312:  375 
• 4j Karim A. Mortreux A. Petit F. Buono G. Pfeiffer G. J. Organomet. Chem.  1986,  317:  93 
• 4k Pracejus G. Pracejus H. J. Mol. Cat.  1984,  24:  227 
• 4l Cesarotti E. Chiesa A. D’Alfonso G. Tetrahedron Lett.  1982,  23:  2995 
• 5 Inoguhi K. Sakuraba S. Achiwa K. Synlett  1992,  169 
• 6 Brunner H. Pieronczyk J. J. Chem. Res., Synop.  1980,  76 
• 7 Nozaki K. Li W. Horiuchi T. Takaya H. Saito T. Yoshida A. Matsumara K. Kato Y. Imai T. Miura T. Kumobayashi H. J. Org. Chem.  1996,  61:  7658 
• 8 Tararov VI. Kadyrov R. Riermeier TH. Holz J. Börner A. Tetrahedron: Asymmetry  1999,  10:  4009 
• 9 Tararov VI. Kadyrov R. Riermeier TH. Holz J. Börner A. Tetrahedron Lett.  2000,  41:  2351 
• 10 Sell T. Laschat S. Dix I. Jones PG. Eur. J. Org. Chem.  2000,  4119 
• 12 Assignment of the absolute configuration of 6a according to: Brunner H. Schönhammer B. Schönhammer B. Steinberger C. Chem. Ber.  1983,  116:  3529 
• 13 Heller D. Drexler H.-J. Spannenberg A. Heller B. You J. Baumann W. Angew. Chem. Int. Ed.  2002,  41:  777 ; Angew. Chem. 2002, 114, 814
• 14 Suarez A. Pizzano A. Tetrahedron: Asymmetry  2001,  12:  2501 
• 15a Felgus S. Landis CR. J. Am. Chem. Soc.  2000,  122:  12714 
• 15b Felgus S. Landis CR. Angew. Chem. Int. Ed.  2000,  39:  2863 ; Angew. Chem. 2000, 112, 2985
• 15c Landis CR. Halpern J. J. Am. Chem. Soc.  1987,  109:  1746 
• 16 Chan ASC. Hu W. Pai C.-C. Lau C.-P. Jiang Y. Mi A. Yan A. Sun J. Lou R. Deng J. J. Am. Chem. Soc.  1997,  119:  9570 

11

Selected spectroscopic data of phosphine phosphinite ligands:
4a: ¹H NMR (500 MHz, CDCl₃): δ = 0.72 (s, 3 H), 0.75-0.85 (m, 1 H), 0.94-1.05 (m, 1 H), 1.10 (s, 3 H), 1.34-1.45 (m, 1 H), 1.52-1.59 (m, 2 H), 1.79 (d, 1 H), 2.12 (d, broad, J = 13.8 Hz, 1 H), 2.12 (dd, J = 13.8/5.0 Hz, 1 H), 2.27 (d, J = 15.0 Hz, 1 H), 4.32 (t, J = 7.5 Hz, 1 H), 6.95-7.54 (m, 20 H); ³¹P NMR (202 MHz, CDCl₃): δ = -24.0 (s), 112.2 (s).
4b: ¹H NMR (500 MHz, CDCl₃): δ = 0.71 (s, 3 H), 0.71-0.82 (m, 2 H), 0.92-1.00 (m, 1 H), 1.11 (s, 3 H), 1.36-1.42 (m, 1 H), 1.53-1.59 (m, 2 H), 1.83 (d, broad, J = 13.8 Hz, 1 H), 2.05 (s, 6 H), 2.11 (dd, J = 13.8/5.0 Hz, 1 H), 2.20 (s, 6 H), 2.26 (d, J = 15.0 Hz, 1 H), 4.25 (t, J = 7.5 Hz, 1 H), 6.72 (s, 1 H), 6.84 (s, 1 H), 6.94-7.51 (m, 14 H); ³¹P NMR (202 MHz, CDCl₃): δ = -23.9 (s), 112.9 (s).
4c: ¹H NMR (500 MHz, CDCl₃): δ = 0.73 (s, 3 H), 0.73-0.85 (m, 2 H), 0.98 (s, 3 H), 0.90-1.85 (m, 28 H), 2.10 (dd, J = 13.8/5.0 Hz, 1 H), 2.33 (d, J = 13.8 Hz, 1 H), 3.90 (t, J = 7.5 Hz, 1 H), 7.05-7.55 (m, 10 H); ³¹P NMR (202 MHz, CDCl₃): δ = -25.7 (s), 143.1 (s).