Photochemical Decarboxylative Formylation of Indoles with Aqueous Glyoxylic Acid

Abstract

A direct metal- and oxidant-free photochemical decarboxylative formylation of indoles with 50% aqueous glyoxylic acid proceeds in good to moderate yields.

Key words

photochemistry - indoles - formylation - decarboxylation - transition-metal-free - glyoxylic acid

Publication History

Received: 04 June 2022

Accepted after revision: 30 June 2022

Article published online:
26 July 2022

• References and Notes

• 1a Vitaku E, Smith DT, Njardarson JT. J. Med. Chem. 2014; 57: 10257
• 1b Ferguson LN. Chem. Rev. 1946; 38: 227
• 1c Newman DJ, Cragg GM. J. Nat. Prod. 2020; 83: 770
• 2a Olah GA, Ohannesian L, Arvanaghi M. Chem. Rev. 1987; 87: 671
• 2b Kantlehner W. Eur. J. Org. Chem. 2003; 2003: 2530
• 3a Jones G, Stanforth SP. Org. React. 2000; 56: 355
• 3b Wynberg H. Chem. Rev. 1960; 60: 169
• 3c Rieche A, Gross H, Höft E. Org. Synth. 1967; 47: 1
• 4a Wu W, Su W. J. Am. Chem. Soc. 2011; 133: 11924
• 4b Zhang L, Peng C, Zhao D, Wang Y, Fu H.-J, Shen Q, Li J.-X. Chem. Commun. 2012; 48: 5928
• 4c Ling F, Cheng D, Liu T, Liu L, Li Y, Li J, Zhong W. Green Chem. 2021; 23: 4107
• 4d Li L.-T, Huang J, Li H.-Y, Wen L.-J, Wang P, Wang B. Chem. Commun. 2012; 48: 5187
• 4e Fei H, Yu J, Jiang Y, Guo H, Cheng J. Org. Biomol. Chem. 2013; 11: 7092
• 4f Liang F, Eda K, Okazoe T, Wada A, Mori N, Konishi K, Tsuda A. J. Org. Chem. 2021; 86: 6504
• 5a Zhang T, Wang N.-X, Xing Y. J. Org. Chem. 2018; 83: 7559
• 5b Yi H, Zhang G, Wang H, Huang Z, Wang J, Singh AK, Lei A. Chem. Rev. 2017; 117: 9016
• 5c Penteado F, Lopes EF, Alves D, Perin G, Jacob RG, Lenardão EJ. Chem. Rev. 2019; 119: 7113
• 5d Rodrίguez N, Gooßen LJ. Chem. Soc. Rev. 2011; 40: 5030
• 6a Huang H, Yu C, Zhang Y, Zhang Y, Mariano PS, Wang W. J. Am. Chem. Soc. 2017; 139: 9799
• 6b Zhang S, Tan Z, Zhang H, Liu J, Xu W, Xu K. Chem. Commun. 2017; 53: 11642
• 6c Dong J, Wang X, Song H, Liu Y, Wang Q. Adv. Synth. Catal. 2020; 362: 2155
• 6d Huang H, Li X, Yu C, Zhang Y, Mariano PS, Wang W. Angew. Chem. Int. Ed. 2017; 56: 1500
• 6e Schwarz J, König B. Green Chem. 2018; 20: 323
• 7a Zhao B, Shang R, Cheng W.-M, Fu Y. Org. Chem. Front. 2018; 5: 1782
• 7b Lyu X.-L, Huang S.-S, Song H.-J, Liu Y.-X, Wang Q.-M. RSC Adv. 2019; 9: 36213
• 7c Xiang Y, Zeng G, Sang X, Li X, Ding Q, Peng Y. Tetrahedron 2021; 91: 132193
• 7d Gooßen LJ, Rodrίguez N, Gooßen K. Angew. Chem. Int. Ed. 2008; 47: 3100
• 8a Xiao P, Pannecoucke X, Bouillon J.-P, Couve-Bonnaire S. Chem. Soc. Rev. 2021; 50: 6094
• 8b Patra T, Maiti D. Chem. Eur. J. 2017; 23: 7382
• 8c Kong D, Moon PJ, Lui EK. J, Bsharat O, Lundgren RJ. Science 2020; 369: 557
• 8d Reddy RS, Lagishetti C, Kiran IN. C, You H, He Y. Org. Lett. 2016; 18: 3818
• 8e Jiraroj D, Jirarattanapochai O, Anutrasakda W, Samec JS. M, Tungasmita DN. Appl. Catal., B 2021; 291: 120050
• 8f You H, Vegi SR, Lagishetti C, Chen S, Reddy RS, Yang X, Guo J, Wang C, He Y. J. Org. Chem. 2018; 83: 4119
• 8g Li B, Matsutani H, Kimura M, Miyatake M, Murakami Y, Katoh S, Tanimoto A, Ma X, Jiang X. RSC Adv. 2021; 11: 20926
• 8h Lagishetti C, Banne S, You H, Tang M, Guo J, Qi N, He Y. Org. Lett. 2019; 21: 5301
• 8i Reddy RS, Zheng S, Lagishetti C, You H, He Y. RSC Adv. 2016; 6: 68199
• 9a Yin Z, Wang Z, Wu X.-F. Org. Biomol. Chem. 2018; 16: 3707
• 9b Lin D.-Z, Huang J.-M. Org. Lett. 2019; 21: 5862
• 10a Li X, Gu X, Li Y, Li P. ACS Catal. 2014; 4: 1897
• 10b Zhao Y, Li H, Yin S, Wu Y, Ni G. Synlett 2022; 54: 659
• 11a Wang Q.-D, Zhou B, Yang J.-M, Fang D, Ren J, Zeng B.-B. Synlett 2017; 28: 2670
• 11b Liu Y, Cai L, Xu S, Pu W, Tao X. Chem. Commun. 2018; 54: 2166
• 11c Cao H, Pu W, Zhang J, Yan P, Zhang J, Xu S. Synlett 2020; 31: 1287
• 12a Shang T.-Y, Lu L.-H, Cao Z, Liu Y, He W.-M, Yu B. Chem. Commun. 2019; 55: 5408
• 12b Jia W, Jian Y, Huang B, Yang C, Xia W. Synlett 2018; 29: 1881
• 12c Cheng W.-M, Shang R, Yu H.-Z, Fu Y. Chem. Eur. J. 2015; 21: 13191
• 13 1H-Indole-3-carboxaldehyde (3a): Typical ProcedureA 10 mL quartz tube was charged with indole (1a; 0.25 mmol, 1 equiv), 50% aq. glyoxylic acid (2; 0.51 mmol, 2 equiv), and MeCN (6.0 mL), and the solution was irradiated with eight 8 W 254 nm UV lamps in a photochemical reactor at rt for 6 h until the reaction was complete (TLC). The reaction was then quenched with H₂O (5 mL) and the mixture was extracted with EtOAc (3 × 5 mL). The extracts were dried (Na₂SO₄) and concentrated in a rotary evaporator, and the crude product was purified by column chromatography [silica gel, EtOAc–hexane (4:6)] to give a yellow solid; yield: 65%; mp 189–191 °C (Lit.^3a 190–192 °C).¹H NMR (500 MHz, DMSO-d ₆): δ = 12.14 (br s, 1 H), 9.95 (s, 1 H), 8.28 (d, J = 3.1 Hz, 1 H), 8.11 (d, J = 7.6 Hz, 1 H), 7.52 (d, J = 7.9 Hz, 1 H), 7.28–7.21 (m, 2 H). ¹³C{¹H} NMR (125 MHz, DMSO-d ₆): δ = 185.44, 138.90, 137.52, 124.59, 123.93, 122.59, 121.30, 118.64, 112.88