ORGANIC LETTERS
Asymmetric Transfer Hydrogenation Coupled with Dynamic Kinetic Resolution in Water: Synthesis of anti-β-Hydroxy-r-amino Acid Derivatives
2012 Vol. 14, No. 24 6334–6337
Brinton Seashore-Ludlow,*,† Franc-ois Saint-Dizier,† and Peter Somfai*,‡,§ Organic Chemistry, Department of Chemical Science and Engineering, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden, Centre for Analysis and Synthesis, Lund University, Box 124, 221 00 Lund, Sweden, and Institute of Technology, University of Tartu, Nooruse 1, 504 11 Tartu, Estonia
[email protected];
[email protected] Received November 12, 2012
ABSTRACT
The use of asymmetric transfer hydrogenation combined with dynamic kinetic resolution for the synthesis of β-hydroxy-R-(tert-butoxycarbonyl)amino esters in water is described. This procedure provides the desired amino alcohols in good yields, diastereoselectivities, and enantioselectivities. A surfactant is employed to achieve good yields due to the hydrophobic nature of both the catalyst and substrate. The reaction setup is operationally simple, and nondegassed water can be used as the solvent.
The development of methods for the stereoselective construction of β-hydroxy-R-amino acids and their derivatives is of signifiant interest due to the high frequency of such architectures in natural products and pharmaceuticals. For example, this particular molecular arrangement is found in sphingosine,1 cyclomarin C,2 the papuamides,3 the thiopeptide antibiotic, GE2270A,4 and vancomycin,5 †
KTH Royal Institute of Technology. Lund University. § University of Tartu. (1) (a) Llaveria, J.; Diaz, Y.; Matheu, M. I.; Castillon, S. Org. Lett. 2008, 11, 205–208. (b) Torssell, S.; Somfai, P. Org. Biomol. Chem. 2004, 2, 1643–1646. (c) van den Berg, R. J. B. H. N.; van den Elst, H.; Korevaar, C. G. N.; Aerts, J. M. F. G.; van der Marel, G. A.; Overkleeft, H. S. Eur. J. Org. Chem. 2011, 2011, 6685–6689. (2) (a) Hamada, Y.; Shioiri, T. Chem. Rev. 2005, 105, 4441–4482. (b) Wen, S.-J.; Yao, Z.-J. Org. Lett. 2004, 6, 2721–2724. (3) Ford, P. W.; Gustafson, K. R.; McKee, T. C.; Shigematsu, N.; Maurizi, L. K.; Pannell, L. K.; Williams, D. E.; Dilip de Silva, E.; Lassota, P.; Allen, T. M.; Van Soest, R.; Andersen, R. J.; Boyd, M. R. J. Am. Chem. Soc. 1999, 121, 5899–5909. (4) Nicolaou, K. C.; Dethe, D. H.; Leung, G. Y. C.; Zou, B.; Chen, D. Y.-K. Chem.;Asian J. 2008, 3, 413–429. (5) (a) Nicolaou, K. C.; Boddy, C. N. C.; Br€ase, S.; Winssinger, N. Angew. Chem., Int. Ed. 1999, 38, 2096–2152. (b) Girard, A.; Greck, C.; Ferroud, D.; Genet, J. P. Tetrahedron Lett. 1996, 37, 7967–7970.
all of which possess important biological properties. Furthermore, derivatives of these compounds can also be used as chiral auxiliaries and chiral building blocks.6 An elegant approach to the desired chiral subunits is the asymmetric transfer hydrogenation (ATH)7 or asymmetric hydrogenation (AH)8 of configurationally labile β-ketoesters bearing an R nitrogen substituent. Such a reaction sequence proceeds through a dynamic kinetic resolution (DKR) and sets the configuration of both stereocenters.9
‡
10.1021/ol303115v r 2012 American Chemical Society Published on Web 12/10/2012
(6) Ager, D. J.; Prakash, I.; Schaad, D. R. Chem. Rev. 1996, 96, 835– 876. (7) (a) Mordant, C.; Dunkelmann, P.; Ratovelomanana-Vidal, V.; Genet, J.-P. Chem. Commun. 2004, 1296–1297. (b) Mohar, B.; Valleix, A.; Desmurs, J.-R.; Felemez, M.; Wagner, A.; Mioskowski, C. Chem. Commun. 2001, 2572–2573. (c) Xu, Z.; Zhu, S.; Liu, Y.; He, L.; Geng, Z.; Zhang, Y. Synthesis 2010, 811–817. (8) (a) Makino, K.; Iwasaki, M.; Hamada, Y. Org. Lett. 2006, 8, 4573–4576. (b) Makino, K.; Goto, T.; Hiroki, Y.; Hamada, Y. Tetrahedron: Asymmetry 2008, 19, 2816–2828. (c) Hamada, Y.; Koseki, Y.; Fujii, T.; Maeda, T.; Hibino, T.; Makino, K. Chem. Commun. 2008, 6206–6208. (d) Hamada, Y.; Makino, K. Stereoselective Synthesis of anti-β-Hydroxy-R-Amino Acids Using anti-Selective Asymmetric Hydrogenation. In Asymmetric Synthesis and Application of R-Amino Acids; American Chemical Society: 2009; Vol. 1009, pp 227 238. (9) Pellissier, H. Tetrahedron 2003, 59, 8291–8327.
Table 1. Optimization of the ATH via DKR Reaction of 1a
entry
methoda
arene/ligand
surfactant (equiv)
XO2CH (equiv)
temp (°C)/time
yieldb
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15e
A A A A A A A A B B B B B B B
p-cymene/3 p-cymene/3 p-cymene/3 p-cymene/3 p-cymene/3 p-cymene/3 p-cymene/3 p-cymene/3 p-cymene/3 p-cymene/4 benzene/5 benzene/5 benzene/5 benzene/5 benzene/5
SDS (0.5 equiv) SDS (0.1 equiv) SDS (1 equiv) SDS (0.5 equiv) SDS (0.5 equiv) SDS (0.5 equiv) SDS (0.5 equiv) SDS (0.5 equiv) SDS (0.5 equiv) SDS (0.5 equiv) CTAB (0.5 equiv) Tween 20 (0.2 equiv) Tween 20 (0.2 equiv) Tween 20 (0.2 equiv)
NaO2CH (5 equiv) NaO2CH (15 equiv) NaO2CH (15 equiv) NaO2CH (15 equiv) LiO2CH (15 equiv) KO2CH (15 equiv) NaO2CH (5 equiv) NaO2CH (5 equiv) NaO2CH (5 equiv) NaO2CH (5 equiv) NaO2CH (5 equiv) NaO2CH (5 equiv) NaO2CH (5 equiv) NaO2CH (5 equiv) NaO2CH (5 equiv)
20 °C/16 h 30 °C/16 h 30 °C/16 h 30 °C/16 h 30 °C/16 h 30 °C/16 h 30 °C/16 h 30 °C/3 d 30 °C/16 h 30 °C/16 h 30 °C/16 h 30 °C/16 h 30 °C/16 h 20 °C/3 d 20 °C/3 d
