Photoredox Trifluoromethylation/Cyclization of N-Arylacrylamides with 4-(Difluoroamino)-1-[(trifluoromethyl)sulfonyl]pyridinium Triflate (TFSP)

Abstract

A photoredox trifluoromethylation/cyclization of N-arylacrylamides with inexpensive stable solid 4-(difluoroamino)-1-[(trifluoromethyl)sulfonyl]pyridinium triflate (TFSP) has been developed.

Key words

trifluoromethylation - cyclization - arylacrylamides - photo­redox reaction - indolones

• References and Notes

• 1a Liu X, Xu C, Wang M, Liu Q. Chem. Rev. 2015; 115: 683
• 1b Ge H, Shen Q. Org. Chem. Front. 2019; 6: 2205
• 1c Bhaskaran RP, Babu PB. Adv. Synth. Catal. 2020; 362: 5219
• 1d Kareem RT, Azizi B, Asnaashariisfahani M, Ebadi A, Vessally E. RSC Adv. 2021; 11: 14941
• 1e Xiao H, Zhang Z, Fang Y, Zhu L, Li C. Chem. Soc. Rev. 2021; 50: 6308
• 1f Baguia H, Evano G. Chem. Eur. J. 2022; 28: e202103599
• 1g Mandal D, Maji S, Pal T, Sinha SK, Maiti D. Chem. Commun. 2022; 58: 10442
• 2a Landelle G, Panossian A, Leroux FR. Curr. Top. Med. Chem. (Sharjah, United Arab Emirates) 2014; 14: 941
• 2b Wei C, Zhang W, Huang J, Li H, Zhou Y, Yu G. Macromolecules 2019; 52: 2911
• 2c Han J, Kiss L, Mei H, Remete AM, Ponikvar-Svet M, Sedgwick DM, Roman R, Fustero S, Moriwaki H, Soloshonok VA. Chem. Rev. 2021; 121: 4678
• 2d Yan L, Li D, Le Y, Dong P, Liu L. Dyes Pigm. 2022; 201: 110200
• 2e Kim SJ, Kang I, Byun T, So J, Kim SY. Polymers (Basel, Switz.) 2022;  14, 501
• 2f Liu X.-H, Wen Y.-H, Cheng L, Xu T.-M, Wu N.-J. J. Agric. Food Chem. 2021; 69: 6968
• 3 For Umemoto’s reagents as trifluoromethylating agents, see: Chen L, Ma P, Yang B, Zhao X, Huang X, Zhang J. Chem. Commun. 2021; 57: 1030

For Togni’s reagents as trifluoromethylating agents, see:
• 4a Xu P, Xie J, Xue Q, Pan C, Cheng Y, Zhu C. Chem. Eur. J. 2013; 19, 14039
• 4b Kong W, Casimiro M, Merino E, Nevado C. J. Am. Chem. Soc. 2013; 135: 14480
• 4c Egami H, Shimizu R, Sodeoka M. J. Fluorine Chem. 2013; 152: 51
• 4d Yang N.-Y, Li Z.-L, Ye L, Tan B, Liu X.-Y. Chem. Commun. 2016; 52: 9052
• 5 For a trifluoroborate salts as trifluoromethylating agents, see: Smirnov VO, Maslov AS, Kokorekin VA, Korlyukov AA, Dilman AD. Chem. Commun. 2018; 54: 2236

For TMSCF₃ as a trifluoromethylating agent, see:
• 6a Mu X, Wu T, Wang H.-Y, Guo Y.-L, Liu G. J. Am. Chem. Soc. 2012; 134: 878
• 6b Li L, Deng M, Zheng S.-C, Xiong Y.-P, Tan B, Liu X.-Y. Org. Lett. 2014; 16: 504
• 6c Fu W, Xu F, Fu Y, Xu C, Li S, Zou D. Eur. J. Org. Chem. 2014; 709
• 6d Lin J.-S, Liu X.-G, Zhu X.-L, Tan B, Liu X.-Y. J. Org. Chem. 2014; 79: 7084

For F₃CI as a trifluoromethylating agent see:
• 7a Tang S, Li Z.-H, Wang M.-W, Li Z.-P, Sheng R.-L. Org. Biomol. Chem. 2015; 13: 5285
• 7b An Y, Li Y, Wu J. Org. Chem. Front. 2016; 3: 570
• 7c Yang Z, Tang A. Synlett 2019; 30: 1061
• 7d Yang Z, Cheng Y, Long J, Feng X, Tang R, Wei J. New J. Chem. 2019; 43: 18760

For F₃CSO₂Cl as a trifluoromethylating agent, see:
• 8a Tang X.-J, Thomson CS, Dolbier WR. Jr. Org. Lett. 2014; 16: 4594
• 8b Tang X.-J, Dolbier WR. Jr. Angew. Chem. Int. Ed. 2015; 54: 4246
• 8c Zheng L, Yang C, Xu Z, Gao F, Xia W. J. Org. Chem. 2015; 80: 5730
• 8d Zhang M, Ding X, Lu A, Kang J, Gao Y, Wang Z, Li H, Wang Q. Org. Chem. Front. 2021; 8: 961
• 8e Muralirajan K, Kancherla R, Bau JA, Taksande MR, Qureshi M, Takanabe K, Rueping M. ACS Catal. 2021; 11: 14772
• 9 For IMDN-SO₂CF₃ as a trifluoromethylating reagent, see: Guo Y, Wang R, Song H, Liu Y, Wang Q. Chem. Commun. 2021; 57: 8284

For F₃CSO₂NHNHBoc as a trifluoromethylating agent, see:
• 10a Guo J.-Y, Wu R.-X, Jin J.-K, Tian S.-K. Org. Lett. 2016; 18: 3850
• 10b Wang H, Xie B, Zhou Y, Cen N, Chen W. Chin. Chem. Lett. 2022; 33: 221
• 11 For PhICF₃Cl as a trifluoromethylating agent, see: Guo XuC, Wang L, Huang W, Wang M. Org. Biomol. Chem. 2019; 17: 4593

For TFAA as a trifluoromethylating reagent, see:
• 12a Beatty JW, Douglas JJ, Cole KP, Stephenson CR. J. Nat. Commun. 2015; 6: 7919
• 12b Kawamura S, Sodeoka M. Angew. Chem. Int. Ed. 2016; 55: 8740
• 13a Liu J, Zhuang S, Gui Q, Chen X, Yang Z, Tan Z. Eur. J. Org. Chem. 2014; 3196
• 13b Zhang L, Li Z, Liu Z.-Q. Org. Lett. 2014; 16: 3688
• 13c Wei W, Wen J, Yang D, Liu X, Guo M, Dong R, Wang H. J. Org. Chem. 2014; 79: 4225
• 13d Yang F, Klumphu P, Liang Y.-M, Lipshutz BH. Chem. Commun. 2014; 50: 936
• 13e Shi L, Yang X, Wang Y, Yang H, Fu H. Adv. Synth. Catal. 2014; 356: 1021
• 13f Lu M, Liu Z, Zhang J, Tian Y, Qin H, Huang M, Hu S, Cai S. Org. Biomol. Chem. 2018; 16: 6564
• 13g Kong R, Fu T, Yang R, Chen D, Dong Y, Li W, Wang B. ChemCatChem 2021; 13: 2952
• 13h Jiang Y.-Y, Dou G.-Y, Xu K, Zeng C.-C. Org. Chem. Front. 2018; 5: 2573
• 13i Ruan Z, Huang Z, Xu Z, Mo G, Tian X, Yu X.-Y, Ackermann L. Org. Lett. 2019; 21: 1237
• 13j Zhang Z, Zhang L, Cao Y, Li F, Bai G, Liu G, Yang Y, Mo F. Org. Lett. 2019; 21: 762
• 14 Li Y, Liang X, Niu K, Gu J, Liu F, Xia Q, Wang Q, Zhang W. Org. Lett. 2022; 24: 5918
• 15a Zhang M, Lin J.-H, Xiao J.-C. Org. Lett. 2021; 23: 6079
• 15b Yang Y.-F, Lin J.-H, Xiao J.-C. Org. Lett. 2021; 23: 9277
• 15c Xiao F, Lin J.-H, Hao F, Zheng X, Guo Y, Xiao J.-C. Org. Chem. Front. 2022; 9: 1982
• 16 Koike T, Akita M. Inorg. Chem. Front. 2014; 1: 562
• 17 1,3-Dimethyl-3-(2,2,2-trifluoroethyl)-1,3-dihydro-2H-indol-2-one (3a); Typical Procedure A dried reaction tube was charged with TFSP (0.25 mmol), 1a (0.20 mmol), PC4 (1 mol%), and Cs₂CO₃ (0.2 mmol). The tube was evacuated and backfilled with argon three times and then anhyd DCM (2.0 mL) was injected into the tube from a syringe. The solution was irradiated with 50 W 440 nm blue LEDs for 12 h. The crude mixture was purified by column chromatography (silica gel) to give a yellow oil; yield: 32.9 mg (68%). ¹H NMR (500 MHz, CDCl₃): δ = 7.33 (td, J = 7.7, 1.2 Hz, 1 H), 7.28 (d, J = 7.5 Hz, 1 H), 7.11 (td, J = 7.5, 1.0 Hz, 1 H), 6.90 (d, J = 7.8 Hz, 1 H), 3.25 (s, 3 H), 2.84 (dq, J = 15.2, 10.7 Hz, 1 H), 2.66 (dq, J = 15.2, 10.5 Hz, 1 H), 1.42 (s, 3 H).