Decarboxylative Oxidation of Carboxylic Acids Using Photocatalysis and Copper Catalysis

Abstract

A decarboxylative oxidation of carboxylic acids was developed through visible-light-induced photocatalysis with molecular oxygen as a green oxidant and copper as a co-catalyst. This reaction worked smoothly on various type of acids, and could potentially be used in modifications of natural products. The high efficiency of this transformation was demonstrated on over 40 substrates.

• References and Notes

• 1a Boto A, Hernández R, Suárez E. J. Org. Chem. 2000; 65: 4930
• 1b Boto A, Hernández R, Suárez E. Tetrahedron Lett. 2000; 41: 2899
• 1c Itoh A, Kodama T, Inagaki S, Masaki Y. Org. Lett. 2000; 2: 331
• 1d Favier I, Duñach E, Hébrault D, Desmurs J. New. J. Chem. 2004; 28: 62
• 1e Habibia MH, Farhadib S. J. Chem. Res., Synop. 2004; 296
• 1f Mirkhani V, Tangestaninejad S, Moghadam M, Moghbel M. Bioorg. Med. Chem. 2004; 12: 903
• 1g Farhadi S, Zaringhadam P, Sahamieh RZ. Tetrahedron Lett 2006; 47: 1965
• 1h Telvekar VN, Sasane KA. Synlett 2010; 2778
• 1i Feng Q, Song Q. J. Org. Chem. 2014; 79: 1867
• 1j Zhang P, Zhang L, Gao Y, Xu J, Fang H, Tang G, Zhao Y. Chem. Commun. 2015; 51: 7839
• 1k Mete TB, Khopade TM, Bhat RG. Tetrahedron Lett 2017; 58: 2822
• 1l Lechner R, Kümmela S, König B. Photochem. Photobiol. Sci. 2010; 9: 1367
• 2a Leung JC. T, Chatalova-Sazepin C, West JG, Rueda-Becerril M, Paquin JF, Sammis GM. Angew. Chem. Int. Ed. 2012; 51: 10804
• 2b Rueda-Becerril M, Mahé O, Drouin M, Majewski MB, West JG, Wolf MO, Sammis GM, Paquin JF. J. Am. Chem. Soc. 2014; 136: 2637
• 2c Ventre S, Petronijevic FR, MacMillan DW. C. J. Am. Chem. Soc. 2015; 137: 5654
• 2d Wu X, Meng C, Yuan X, Jia X, Qian X, Ye J. Chem. Commun. 2015; 51: 11864
• 3 Noble A, MacMillan DW. C. J. Am. Chem. Soc. 2014; 136: 11602
• 4 Le Vaillant F, Courant T, Waser J. Angew. Chem. Int. Ed. 2015; 54: 11200
• 5a Cassani C, Bergonzini G, Wallentin C.-J. Org. Lett. 2014; 16: 4228
• 5b Griffin JD, Zeller MA, Nicewicz DA. J. Am. Chem. Soc. 2015; 137: 11340
• 6 Song H.-T, Ding W, Zhou Q.-Q, Liu J, Lu-Q L, Xiao W.-J. J. Org. Chem. 2016; 81: 7250
• 7 Chu L, Ohta C, Zuo Z, MacMillan DW. C. J. Am. Chem. Soc. 2014; 136: 10886
• 8a Zuo Z, MacMillan DW. C. J. Am. Chem. Soc. 2014; 136: 5257
• 8b Jin Y, Fu H. Asian J. Org. Chem. 2017; 6: 368
• 8c Xuan J, Zhang Z.-G, Xiao W.-J. Angew. Chem. Int. Ed. 2015; 54: 15632
• 9a Sakakibara Y, Cooper P, Murakami K, Itami K. Chem. Asian J. 2018; 13: 2410
• 9b Faraggi TM, Li W, MacMillan DW. C. Isr. J. Chem. 2020; 60: 410
• 9c Guan R, Bennett EL, Huang Z, Xiao J. Green Chem. 2022; 24: 2946
• 9d Reichle A, Sterzel H, Kreitmeier P, Fayad R, Castellano FN, Rehbein J, Reiser O. Chem. Commun 2022; 58: 4456
• 9e Tu J.-L, Gao H, Luo M, Zhao L, Yang C, Guo L, Xia W. Green Chem 2022; 24: 5553
• 10 Li R, Dong Y, Khan SN, Zaman MK, Zhou J, Miao P, Hu L, Sun Z. Nat. Commun. 2022; 13: 7061
• 11a Shirase S, Tamaki S, Shinohara K, Hirosawa K, Tsurugi H, Satoh T, Mashima K. J. Am. Chem. Soc 2020; 142: 5668
• 11b Meng X, Xu H, Zheng Y, Luo J, Huang S. ACS Sustainable Chem. Eng. 2022; 10: 5067
• 12 Photocatalytic Decarboxylation: General Procedure A 25 mL round-bottom flask equipped with a stirrer bar was charged with the appropriate substrate 1 (0.5 mmol, 1.0 equiv), [Ir(dF(CF₃)ppy)₂(dtbpy)]PF₆ (16.9 mg, 3 mol%), CuO (7.9 mg, 20 mol%), bathophenanthroline (41 mg, 25mol%), and Cs₂CO₃(243 mg, 1.5 equiv). DCM (10 mL) was added, then the flask was quickly degassed three times and flushed with O₂ from a balloon. The mixture was heated to 40 °C and irradiated with six 100 W blue LEDs (5 cm away) for 40 h. When the reaction was complete, the solvent was removed under a vacuum and the mixture was purified by flash chromatography (silica gel, PE–EtOAc). Benzyl 4-Oxopiperidine-1-carboxylate (2a) Prepared by the general procedure as a yellow liquid; yield: 99 mg (85%). IR (KBr): 2359, 1699, 1630, 1429, 1353 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 7.36–7.28 (m, 5 H), 5.15 (s, 2 H), 3.76 (t, J = 6.3 Hz, 4 H), 2.42 (t, J = 5.9 Hz, 4 H). ¹³C NMR (101 MHz, CDCl₃): δ = 207.09, 155.05, 136.32, 128.54, 128.20, 127.99, 67.55, 43.07, 40.99. HRMS (ESI): m/z [M + Na]⁺ calcd for C₁₃H₁₅NNaO₃: 256.0944; found: 256.0910. The spectra matched those reported in Ref. 10. 4-Fluorobenzaldehyde (2b) Prepared by the general procedure as a yellow liquid; yield: 45.5 mg (73%). IR (KBr): 1652, 1632, 1585, 1373, 1350 cm^–1. ¹H NMR (400 MHz, CDCl₃): δ = 9.96 (s, 1 H), 7.96–7.85 (m, 2 H), 7.21 (t, J = 8.5 Hz, 2 H). MS (ESI): m/z = 147.1 [M + Na]⁺. The spectra matched those reported in Ref. 11.