Nitroarenes as EnT Photocatalysts for the Cyclopropanation of Cinnamyl Chlorides

Dedication

Dedicated to Prof. Franziska Schoenebeck in recognition of her 2025 Women in Chemistry Award.

Abstract

Nitroarenes are versatile building blocks in organic synthesis, and their photochemical reactivity has recently enabled new transformations, including oxidative cleavage reactions. Here, we disclose a sustainable isomerization strategy in which nitroarenes function as energy-transfer (EnT) photocatalysts to convert cinnamyl chlorides into cyclopropanes. In contrast to conventional methods that rely on transition-metal photocatalysts, this approach capitalizes on the intrinsic triplet energy of nitroarenes, offering a metal-free and operationally simple solution. Preliminary studies indicate that the π,π* triplet state of nitroarenes is more efficient in EnT than the n,π* state, revealing a distinct divergence in their excited-state reactivity. Standard silica gel (SiO₂) serves as an effective additive to promote the reverse isomerization of the resulting 1-arylallyl chlorides to cinnamyl chlorides, further enhancing the overall process efficiency.

Keywords

Nitroarenes - Energy transfer - Cyclopropane - Photocatalysis

Publication History

Received: 20 October 2025

Accepted after revision: 24 December 2025

Accepted Manuscript online:
30 December 2025

Article published online:
22 January 2026

• References

• 1 Booth G. Nitro Compounds, Aromatic. New York: Wiley-VCH Verlag GmbH & Co. KGaA; 2000
• 2 Nepali K, Lee H-Y, Liou J-P. J Med Chem 2019; 62: 2851
• 3 Orlandi M, Brenna D, Harms R, Jost S, Benaglia M. Org Process Res Dev 2018; 22: 430
• 4 Wegener G, Brandt M, Duda L. et al. Appl Catal A Gen 2001; 221: 303
• 5a Adam DJ, Clark JH. Chem Soc Rev 1999; 28: 225
• 5b Mąkosza M. Chem Eur J 2014; 20: 5536
• 6 Döpp D. Wild UP. In: Reactions of Aromatic Nitro Compounds Via Excited Triplet States. Döpp D, Dürr H. eds. Berlin: Springer; 1975
• 7a Olivier W, Błyszczyk PT, Arpa EM. et al. Science 2025; 387: 1167
• 7b Ruffoni A, Hampton C, Simonetti M, Leonori D. Nature 2022; 510: 81
• 7c Sanchez-Bento R, Roure B, Llaveria J, Ruffoni A, Leonori D. Chem 2023; 9: 3685
• 7d Hampton D, Simonetti M, Leonori D. Angew Chem Int Ed 2022; 62: e202214508
• 7e Mykura R, Sánchez-Bento R, Matador E. et al. Nat Chem 2024; 16: 771
• 8a Wise DE, Gogarnoiu ES, Duke AD. et al. J Am Chem Soc 2022; 144: 15437
• 8b Paolillo JM, Duke AD, Gogarnoiu ES, Wise DE, Parasram M. J Am Chem Soc 2023; 145: 2794
• 8c Mitchell JK, Hussain WA, Bansode AH. et al. Org Lett 2023; 25: 6517
• 8d Paolillo JM, Saleh MR, Junk EW, Parasram M. Org Lett 2011; 2025: 27
• 9a Göttemann LT, Wiesler S, Sarpong R. Chem Sci 2024; 15: 213
• 9b Qin H, Liu R, Wang Z. et al. Angew Chem Int Ed 2024; 137: e202416923
• 9c Cui R, Liao Q, Zhao Y. et al. Org Lett 2024; 26: 8222
• 9d Guo X, Cui X, Lu M, Zhou Q-L, Xu W, Ye M. Nat Commun 2025; 16: 4504
• 9e Dixit A, Jana SK, Jati A. et al. Org Lett 2025; 27: 5669
• 9f Cuomo VD, Romano C, Romano C, Procter DJ. Angew Chem Int Ed 2025; 64: e202509244
• 10 Xue T, Ma C, Liu L, Xiao C, Ni S-F, Zeng R. Nat Commun 2024; 15: 1455
• 11a Hölzl-Hobmeier A, Bauer A, Silva AV, Huber SM, Bannwarth C, Bach T. Nature 2018; 564: 240
• 11b Faßbender SI, Molloy JJ, Mück-Lichtenfeld C, Gilmour R. Angew Chem Int Ed 2019; 58: 18619
• 11c Zhang Z, Tilby MJ, Leonori D. Nat Synth 2024; 3: 1221
• 12a Neveselý T, Wienhold M, Molloy JJ, Gilmour R. Chem Rev 2022; 122: 2650
• 12b Strieth-Kalthoff F, James MJ, Teders M, Pitzer L, Glorius F. Chem Soc Rev 2018; 47: 7190
• 12c Dutta S, Erchinger JE, Strieth-Kalthoff F, Kleinmans R, Glorius F. Chem Soc Rev 2024; 53: 1068
• 12d Zhou Q-Q, Zou Y-Q, Lu L-Q, Xiao W-J. Angew Chem Int Ed 2018; 58: 1586
• 13a Hurely R, Testa AC. J Am Chem Soc 1949; 1968: 90
• 13b Fournier T, Tavender SM, Parker AW, Scholes GD, Phillips D. J Phys Chem A 1997; 101: 5320
• 13c Fournier T, Scholes GD, Gould IR, Tavender SM, Phillips D, Parker AW. Laser Chem 1999; 19: 397
• 13d Anderson Jr RW, Hochstrasser RM, Lutz H, Scott GW. J Chem Phys 1974; 61: 2500
• 14 Rihtaršič M, Kweon B, Błyszczyk PT, Ruffoni A, Arpa EM, Leonori D. Nat Catal 2025; in press
• 15 Xu B, Troian-Gautier L, Dykstra R, Martin RT, Gutierrez O, Tambar UK. J Am Chem Soc 2020; 142: 6206
• 16 Talele TT. J Med Chem 2016; 59: 8712
• 17a Tsuga Y, Katou M, Kuwabara S. et al. Chem Asian J 2019; 14: 2067
• 17b Kanamori T, Miki Y, Katou M, Ogura S, Yuasa H. Bioorg Med Chem 2022; 61: 116737
• 17c Kanamori T, Kaneko S, Hamamoto K, Yuasa H. Sci Rep 2023; 13: 288
• 17d Du Y, Kanamor T, Yaginuma Y, Yoshida N, Kaneko S, Yuasa H. Bioorg Med Chem Lett 2024; 114: 129988
• 18a Shandala MY, Khalil SM, Al-Dabbagh MS. Tetrahedron 1984; 40: 1195
• 18b Shandala MY, Waight ES, Weinstock M. J Chem Soc B 1966; 590
• 18c DeWolfe RH. In: Comprehensive Chemical Kinetics. Bamford CH, Tipper CFH. eds. Amsterdam: Elsevier; 1973: 421
• 18d Valkanas G, Waight ES, Weinstock M. J Chem Soc 1963; 4248
• 19 Valkanas G, Waight ES. J Chem Soc 1959; 2720
• 20 Dittmer DC, Marcantonio AF. J Org Chem 1964; 29: 3473
• 21 Zhuravlev LT. Colloids Surf A Physicochem Eng Asp 2000; 173: 1