ORGANIC LETTERS
Iron Porphyrin-Catalyzed Three-Component Reaction of Ethyl Diazoacetate with Aliphatic Amines and β,γ-Unsaturated r‑Keto Esters
2013 Vol. 15, No. 24 6140–6143
Chaoqun Ma, Dong Xing,* Changwei Zhai, Jiuwei Che, Shunying Liu, Jue Wang, and Wenhao Hu* Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, East China Normal University, 3663 North Zhongshan Rd., Shanghai 200062, China
[email protected];
[email protected] Received October 21, 2013
ABSTRACT
An iron porphyrin-catalyzed three-component reaction of ethyl diazoacetate with aliphatic amines and β,γ-unsaturated R-keto esters is reported. The use of iron porphyrin catalyst allows aliphatic amines to be used as the substrate without encountering catalyst poisoning issue and a series of β-hydroxy-R-amino esters are produced in high yields with excellent regioselectivities.
Metal carbenoids generated from diazo compounds with transition-metal catalysts can undergo a variety of important synthetic transformations such as cyclopropanation, X H (X = C, N, O, Si, S) insertion, and ylide formation.1 In recent years, multicomponent reactions (MCRs) based on the trapping of ylide intermediates with different types of electrophiles have greatly enriched the arsenal of carbenoid chemistry and become a powerful tool for the synthesis of polyfunctional molecules.2 4 In these types of MCRs, Rh(II) catalysts were most generally used (1) For leading reviews, see: (a) Doyle, M. P.; McKervey, M. A.; Ye, T. Modern Catalytic Methods for Organic Synthesis with Diazo Compounds; Wiley: New York, 1998. (b) Li, A.-H.; Dai, L.-X.; Aggarwal, V. K. Chem. Rev. 1997, 97, 2341. (c) Davies, H. M. L.; Manning, J. R. Nature 2008, 451, 417. (d) Sun, X.-L.; Tang, Y. Acc. Chem. Res. 2008, 41, 937. (e) Zhang, Z.; Wang, J. Tetrahedron 2008, 64, 6577. (f) Zhu, S.-F.; Zhou, Q.-L. Acc. Chem. Res. 2012, 45, 1365. (g) Zhao, X.; Zhang, Y.; Wang, J. Chem. Commun. 2012, 48, 10162. (2) For selected MCRs via the trapping of oxonium ylides, see: (a) Huang, H. X.; Guo, X.; Hu, W. H. Angew. Chem., Int. Ed. 2007, 46, 1337. (b) Guo, X.; Huang, H. X.; Yang, L. P.; Hu, W. H. Org. Lett. 2007, 9, 4721. (c) Hu, W. H.; Xu, X. F.; Zhou, J.; Liu, W. J.; Huang, H. X.; Hu, J.; Yang, L. P.; Gong, L. Z. J. Am. Chem. Soc. 2008, 130, 7782. (d) Zhang, X.; Huang, H.; Guo, X.; Guan, X.; Yang, L.; Hu, W. Angew. Chem., Int. Ed. 2008, 47, 6647. (e) Zhu, Y. G.; Zhai, C. W.; Yang, L. P.; Hu, W. H. Chem. Commun. 2010, 46, 2865. 10.1021/ol403011r r 2013 American Chemical Society Published on Web 11/19/2013
for their high efficiency in decomposing diazo compounds into carbenoids. However, in certain types of MCRs, the rhodium catalyst was limited in its use to a narrow selection of substrates and undesired side reactions owing to catalyst poisoning and its excessive efficiency.1a,5 For example, in the Rh(II)-catalyzed ammonium ylide trapping process, in order to avoid catalyst poisoning, only less basic aromatic
(3) For selected MCRs via the trapping of ammonium ylides, see: (a) Jiang, J.; Xu, H.-D.; Xi, J.-B.; Ren, B.-Y.; Lv, F.-P.; Guo, X.; Jiang, L.-Q.; Zhang, Z.-Y.; Hu, W.-H. J. Am. Chem. Soc. 2011, 133, 8428. (b) Zhu, Y.; Zhai, C.; Yang, L.; Hu, W. Eur. J. Org. Chem. 2011, 2011, 1113. (c) Zhou, C.-Y.; Wang, J.-C.; Wei, J.; Xu, Z.-J.; Guo, Z.; Low, K.-H.; Che, C.-M. Angew. Chem., Int. Ed. 2012, 51, 11376. (d) Song, J.; Guo, C.; Adele, A.; Yin, H.; Gong, L.-Z. Chem.;Eur. J. 2013, 19, 3319. (e) Jiang, J.; Ma, X.; Liu, S.; Qian, Y.; Lv, F.; Qiu, L.; Wu, X.; Hu, W. Chem. Commun. 2013, 49, 4238. (4) For MCRs via the trapping of zwitterionic intermediate, see: (a) Qiu, H.; Li, M.; Jiang, L.-Q.; Lv, F.-P.; Zan, L.; Zhai, C.-W.; Doyle, M. P.; Hu, W.-H. Nat. Chem. 2012, 4, 733. (b) Li, M.; Zan, L.; Prajapati, D.; Hu, W. Org. Biomol. Chem. 2012, 10, 8808. (c) Xing, D.; Jing, C.; Li, X.; Qiu, H.; Hu, W. Org. Lett. 2013, 15, 3578. (5) Amine poisoning effect with rhodium catalysts has been reported; see: (a) Aller, E.; Buck, R. T.; Drysdale, M. J.; Ferris, L.; Haigh, D.; Moody, C. J.; Pearson, N. D.; Sanghera, J. B. J. Chem. Soc., Perkin Trans. 1 1996, 0, 2879. (b) Aviv, I.; Gross, Z. Chem.;Eur. J. 2008, 14, 3995.
amines could be used, and to avoid undesired side reactions such as dimerization, gradual addition of the diazo compounds is generally required, thus limiting the synthetic value of such methodologies.3 On the other hand, rhodium catalysts are relatively expensive. Toward these ends, the search for alternatively efficient yet cheap and widely available metal catalysts that can overcome the abovementioned drawbacks of rhodium catalysts is of great importance for both the development of new types of MCRs and economic considerations.1f,g
Scheme 1. Iron Porphyrin-Catalyzed Three-Component Reaction
Table 1. Reaction Condition Optimizationa
entry
cat.
solvent
yieldb (%)
dr (syn:anti)c
1 2 3d 4d 5d 6 7 8 9 10 11e 12
Fe(TPP)Cl Rh2(OAc)4 CuPF6(MeCN)4 Cu(OTf)2 Fe(TPP)Cl Fe(TPP)Cl Fe(TPP)Cl Fe(TPP)Cl Fe(TPP)Cl Fe(TPP)Cl Fe(TPP)Cl
CH2Cl2 CH2Cl2 CH2Cl2 CH2Cl2 CH2Cl2 toluene DCE CHCl3 EtOAc Et2O CHCl3 CHCl3
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