Synlett, Inhaltsverzeichnis Synlett 2020; 31(07): 695-698DOI: 10.1055/s-0039-1691587 letter © Georg Thieme Verlag Stuttgart · New York Diiodine-Mediated Oxidative Reaction for the Construction of Imidazo[1,5-a]pyridines under Metal-Free Conditions Kexin Su a State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Gansu Lanzhou, 730000, P. R. of China eMail: chenbh@lzu.edu.cn , Mingda Qin a State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Gansu Lanzhou, 730000, P. R. of China eMail: chenbh@lzu.edu.cn , Yongxin Chen b Key Laboratory of Petroleum Resources, Gansu Lanzhou, 730000, P. R. of China eMail: chenyongxin@lzb.ac.cn , Yafeng Liu a State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Gansu Lanzhou, 730000, P. R. of China eMail: chenbh@lzu.edu.cn , Yuan Tian a State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Gansu Lanzhou, 730000, P. R. of China eMail: chenbh@lzu.edu.cn , Baohua Chen ∗ a State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Gansu Lanzhou, 730000, P. R. of China eMail: chenbh@lzu.edu.cn › Institutsangaben Artikel empfehlen Abstract Artikel einzeln kaufen Alle Artikel dieser Rubrik Abstract An efficient and general protocol has been developed for preparing imidazo[1,5-a]pyridines in moderate to excellent yields by an I2-mediated sequential dual oxidative C(sp3)–H amination of ethyl pyridin-2-ylacetates with benzylamines. The metal- and peroxide-free reaction involves oxidative dehydrogenation and two C–N couplings. Key words Key wordsimidazopyridines - metal-free synthesis - amination - benzylic amines - ethyl pyridinylacetates Volltext Referenzen References and Notes 1a Chen C.-Y, Hu W.-P, Yan P.-C, Senadi G.-C, Wang J.-J. Org. Lett. 2013; 15: 6116 1b Wang H, Wang Y, Peng C, Zhang J, Zhu Q. J. Am. Chem. 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Lett. 2008; 10: 889 15 Ethyl 3-Phenylimidazo[1,5-a]pyridine-1-carboxylate (3aa); Typical Procedure A 10-mL Schlenk tube was charged with 1a (0.2 mmol), 2a (1.1 equiv, 0.22 mmol), and I2 (1 equiv, 0.2 mmol). CH2Cl2 (2 mL) was then added and the mixture was stirred at 100 ℃ for 8 h under air. The solvent was removed, and the mixture was filtered and evaporated under vacuum. The residue was purified by column chromatography [silica gel, EtOAc–PE (10:1)] to give a white solid; yield: 88%; mp 127–130 °C. 1H NMR (300 MHz, CDCl3): δ = 8.28 (dd, J = 16.6, 8.2 Hz, 2 H), 7.79 (d, J = 6.6 Hz, 2 H), 7.57–7.46 (m, 3 H), 7.13 (dd, J = 8.9, 6.7 Hz, 1 H), 6.78 (t, J = 6.8 Hz, 1 H), 4.50 (q, J = 7.1 Hz, 2 H), 1.47 (t, J = 7.1 Hz, 3 H). 13C NMR (75 MHz, CDCl3): δ = 163.8, 139.4, 135.6, 129.8, 129.3, 129.2, 129.0, 124.5, 122.7, 121.9, 120.2, 114.7, 60.6, 14.9. Zusatzmaterial Zusatzmaterial Supporting Information
