Asymmetric Tandem Reduction of 2-(Aroylmethyl)quinolines with Phosphine-Free Ru-TsDPEN Catalyst

Abstract

The phosphine-free ruthenium complex containing chi-ral N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine (TsDPEN) showed excellent stereoselectivity in the tandem asymmetric reduction of 2-(aroylmethyl)quinolines. The reaction involves transfer hydrogenation of aromatic ketones and hydrogenation of quinolines, giving 1,2,3,4-tetrahydroquinoline derivatives with up to 99% ee and 95:5 dr.

Key words

asymmetric catalysis - tandem reaction - quinolines - ­ruthenium - hydrogenation

References and Notes

• For recent reviews, see:
• 1a Glorius F. Org. Biomol. Chem.  2005,  3:  4171 
• 1b Zhou Y.-G. Acc. Chem. Res.  2007,  40:  1357 
• 1c Kuwano R. Heterocycles  2008,  76:  909 
• 2 Wang W.-B. Lu S.-M. Yang P.-Y. Han X.-W. Zhou Y.-G. J. Am. Chem. Soc.  2003,  125:  10536 
• For selected recent examples of asymmetric hydrogenation of quinolines, see:
• 3a Lu S.-M. Han X.-W. Zhou Y.-G. Adv. Synth. Catal.  2004,  346:  909 
• 3b Wang D.-W. Wang X.-B. Wang D.-S. Lu S.-M. Zhou Y.-G. Li Y.-X.
  J. Org. Chem.  2009,  74:  2780 
• 3c Wang D.-S. Zhou Y.-G. Tetrahedron Lett.  2010,  51:  3014 
• 3d Xu L.-J. Lam KH. Ji JX. Fan Q.-H. Lo W.-H. Chan ASC. Chem. Commun.  2005,  1390 
• 3e Tang W.-J. Zhu S.-F. Xu L.-J. Zhou Q.-L. Fan Q.-H. Zhou H.-F. Lam K. Chan ASC. Chem. Commun.  2007,  613 
• 3f Wang ZJ. Deng GJ. Li Y. He YM. Tang WJ. Fan QH. Org. Lett.  2007,  9:  1243 
• 3g Reetz M. Li X. Chem. Commun.  2006,  2159 
• 3h Mršić N. Lefort L. Boogers JAF. Minnaard AJ. Feringa BL. de Vries JG. Adv. Synth. Catal.  2008,  350:  1081 
• 3i Tadaoka H. Cartigny D. Nagano T. Gosavi T. Ayad T. Genêt JP. Ohshima T. Ratovelomanana-Vidal V. Mashima K. Chem. Eur. J.  2009,  15:  9990 
• 4a Zhou HF. Li ZW. Wang ZJ. Wang TL. Xu LJ. He YM. Fan Q.-H. Pan J. Gu LQ. Chan ASC. Angew. Chem. Int. Ed.  2008,  47:  8464 
• 4b Wang Z.-J. Zhou H.-F. Wang T.-L. He Y.-M. Fan Q.-H. Green Chem.  2009,  11:  767 
• 4c Li Z.-W. Wang T.-L. He Y.-M. Wang Z.-J. Fan Q.-H. Pan J. Xu L.-J. Org. Lett.  2008,  10:  5265 
• For selected examples of asymmetric hydrogenation of other heteroaromatic compounds, see: For indoles and pyrroles:
• 5a Kuwano R. Sato K. Kurokawa T. Karube D. Ito Y. J. Am. Chem. Soc.  2000,  122:  7614 
• 5b Wang D.-S. Chen Q.-A. Li W. Yu C.-B. Zhou Y.-G. Zhang X. J. Am. Chem. Soc.  2010,  132:  8909 
• 5c Kuwano R. Kashiwabara M. Ohsumi M. Kusano H. J. Am. Chem. Soc.  2008,  130:  808 
• 5d For furans, see: Kaiser S. Smidt SP. Pfaltz A. Angew. Chem. Int. Ed.  2006,  45:  5194 
• 5e For pyridines, see: Legault CY. Charette AB. J. Am. Chem. Soc.  2005,  127:  8966 
• 5f For isoquinolines, see: Lu SM. Wang YQ. Han XW. Zhou Y.-G. Angew. Chem. Int. Ed.  2006,  45:  2260 
• For quinoxalines, see:
• 5g Tang W.-J. Xu L.-J. Fan Q.-H. Wang J. Fan B.-M. Lam K.-H. Chan ASC. Angew. Chem. Int. Ed.  2009,  48:  9135 
• 5h Mršić N. Jerphagnon T. Minnaard AJ. Feringa BL. de Vries JG. Adv. Synth. Catal.  2009,  351:  2549 
• 6 Carey ARE. Fukata G. O’Ferrall RAM. Murphy MG. J. Chem. Soc., Perkin Trans. 2  1985,  1711 
• For metal complexes containing diamine ligands for asymmetric hydrogenation, see:
• 7a Ito M. Hirakawa M. Murata K. Ikariya T. Organometallics  2001,  20:  379 
• 7b Ohkuma T. Utsumi N. Tsutsumi K. Murata K. Sandoval CA. Noyori R. J. Am. Chem. Soc.  2006,  128:  8724 
• 7c Ohkuma T. Tsutsumi K. Utsumi N. Arai N. Noyori R. Murata K. Org. Lett.  2007,  9:  255 
• 7d Li C. Xiao J. J. Am. Chem. Soc.  2008,  130:  13208 
• 7e Chen f. Wang T.-L. He Y.-M. Ding Z.-Y. Li Z.-W. Xu L.-J. Fan Q.-H. Chem. Eur. J.  2011,  17:  1109 
• 8 Wang X.-B. Wang D.-W. Lu S.-M. Yu C.-B. Zhou Y.-G. Tetrahedron: Asymmetry  2009,  20:  1040 
• 9a Noyori R. Hashiguchi S. Acc. Chem. Res.  1997,  30:  97 
• 9b Hashiguchi S. Fujii A. Takehara J. Ikariya T. Noyori R. J. Am. Chem. Soc.  1995,  117:  7562 
• 10 Sidler DR. Sager JW. Bergan JJ. Wells KM. Bhupathy M. Volante RP. Tetrahedron: Asymmetry  1997,  8:  161 
• 11 For transition-metal-catalyzed asymmetric transfer hydrogenation of quinolines in acidic aqueous buffer solution, see: Wang C. Li C. Wu X. Pettman A. Xiao J. Angew. Chem. Int. Ed.  2009,  48:  6524 

12

Typical procedure for the Ru-catalyzed asymmetric ATH/AH reactions: Into a 50 mL glass-lined stainless steel reactor with a magnetic stirring bar was charged (R,R)-1b (0.6 mg, 0.001 mmol), substrate 2a (24.7 mg, 0.1 mmol) and degassed EtOH (1 mL) under a nitrogen atmosphere, and the mixture was stirred at r.t. for 24 h. Then, to the reaction mixture was added a solution of 1.0 M TfOH in EtOH (100 µL, 0.001 mmol, 1 mol% cf substrate) under a nitrogen atmosphere. The autoclave was closed, and H₂ was initially introduced into the autoclave at a pressure of 50 atm, before being reduced to 1 atm. After this procedure was repeated three times, the autoclave was pressurized with H₂ to 50 atm. Subsequently, the mixture was stirred under this H₂ pressure at r.t. for another 12 h. After carefully releasing the hydrogen, the mixture was concentrated to afford the crude product. The conversion and diastereoselectivity were determined by ^¹H NMR analysis of the crude product. Further purification was performed with a silica gel column (PE-CH₂Cl₂, 1:1) to give the pure product, (+)-1-phenyl-2-(1,2,3,4-tetrahydroquinolin-2-yl)ethanol (4a). Isolated yield: 94%; >95:5 dr; >99% ee; [α] _d ^²0 +67.9 (c 1.00, CHCl₃); ^¹H NMR (300 MHz, CDCl₃): δ = 7.38-7.29 (m, 5 H), 7.00-6.95 (m, 2 H), 6.67-6.62 (m, 1 H), 6.49 (d, J = 7.8 Hz, 1 H), 5.02 (t, J = 6.6 Hz, 1 H), 3.55-3.47 (m, 1 H), 2.88-2.69 (m, 2 H), 1.97-1.90 (m, 3 H), 1.88-1.81 (m, 1 H); ^¹³C NMR (75 MHz, CDCl₃): δ = 143.34, 143.14, 128.30, 127.56, 126.61, 125.70, 124.69, 120.69, 116.73, 113.99, 71.07, 47.79, 43.67, 26.95, 25.15; HRMS (ESI): m/z [M + H]⁺ calcd for C1₇H₂₀NO: 254.15394; found: 254.15385.