Catalyst recovery is an integral part of photoredox catalysis. It is often solved by adding another component-a sacrificial agent-whose role is to convert the catalyst back into its original oxidation state. However, an additive may cause a side reaction thus decreasing the selectivity and overall efficiency. Herein, we present a novel approach towards chemoselective photooxidation reactions based on suitable solvent-acetonitrile acting simultaneously as an electron acceptor for catalyst recovery, and on anaerobic conditions. This is allowed by the unique properties of the catalyst, 7,8-dimethoxy-3-methyl-5-phenyl-5-deazaflavinium chloride existing in both strongly oxidizing and reducing forms, whose strength is increased by excitation with visible light. Usefulness of this system is demonstrated in chemoselective dehydrogenations of 4-methoxy- and 4-chlorobenzyl alcohols to aldehydes without over-oxidation to benzoic acids achieving yields up to 70 %. 4-Substituted 1-phenylethanols were oxidized to ketones with yields 80-100 % and, moreover, with yields 31-98 % in the presence of benzylic methyl group, diphenylmethane or thioanisole which are readily oxidized in the presence of oxygen but these were untouched with our system. Mechanistic studies based on UV-Vis spectro-electrochemistry, EPR and time-resolved spectroscopy measurements showed that the process involving an electron release from an excited deazaflavin radical to acetonitrile under formation of solvated electron is crucial for the catalyst recovery.

Central Laboratories University of Chemistry and Technology Prague Technická 5 166 28 Prague 6 Czech Republic

Department of Inorganic Chemistry University of Chemistry and Technology Prague Technická 5 166 28 Prague 6 Czech Republic

Department of Organic Chemistry University of Chemistry and Technology Prague Technická 5 166 28 Prague 6 Czech Republic

Institute of Organic Chemistry and Biochemistry Academy of Science of the Czech Republic Flemingovo nám 2 16610 Prague 6 Czech Republic

Institute of Organic Chemistry University of Regensburg Universitätsstrasse 31 93040 Regensburg Germany

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I. P. Beletskaya, C. Nájera, M. Yus, Chem. Soc. Rev. 2020, 49, 7101-7166;

R. A. Shenvi, D. P. O'Malley, P. S. Baran, Acc. Chem. Res. 2009, 42, 530-541.

A. Yoshimura, V. V. Zhdankin, Chem. Rev. 2016, 116, 3328-3435;

M. Uyanik, K. Ishihara, Chem. Commun. 2009, 2086-2099.

S. Alvi, V. Jayant, R. Ali, ChemistrySelect 2022, 7, e202200704;

B. Yu, A.-H. Liu, L.-N. He, B. Li, Z.-F. Diao, Y.-N. Li, Green Chem. 2012, 14, 957-962.

L. D′Accolti, C. Annese, C. Fusco, Chem. Eur. J. 2019, 25, 12003-12017;

I. Triandafillidi, D. I. Tzaras, C. G. Kokotos, ChemCatChem 2018, 10, 2521-2535.

R. Yazaki, Chem. Pharm. Bull. 2021, 69, 516-525;

H. Sterckx, B. Morel, B. U. W. Maes, Angew. Chem. Int. Ed. 2019, 58, 7946-7970;

Angew. Chem. 2019, 131, 8028-8055;

M. N. Kopylovich, A. P. C. Ribeiro, E. C. B. A. Alegria, N. M. R. Martins, L. M. D. R. S. Martins, A. J. L. Pombeiro, in Adv. Organomet. Chem., Vol. 63 (Ed.: P. J. Pérez), Academic Press, 2015, pp. 91-174.

L. Marais, A. J. Swarts, Catalysts 2019, 9, 395;

in Catalytic Oxidation in Organic Synthesis, Georg Thieme Verlag, Stuttgart, 2018;

S. Hamada, T. Furuta, Y. Wada, T. Kawabata, Angew. Chem. Int. Ed. 2013, 52, 8093-8097;

Angew. Chem. 2013, 125, 8251-8255;

R. A. Sheldon, I. W. C. E. Arends, Adv. Synth. Catal. 2004, 346, 1051-1071.

J.-E. Bäckvall, Editor, Modern Oxidation Methods, 2nd Completely Revised, Wiley-VCH Verlag GmbH & Co. KGaA, 2010;

L. Melone, C. Punta, Beilstein J. Org. Chem. 2013, 9, 1296-1310;

L. De Luca, G. Giacomelli, A. Porcheddu, J. Org. Chem. 2001, 66, 7907-7909.

N. Holmberg-Douglas, D. A. Nicewicz, Chem. Rev. 2022, 122, 1925-2016;

Y. Lee, M. S. Kwon, Eur. J. Org. Chem. 2020, 2020, 6028-6043;

D. Petzold, M. Giedyk, A. Chatterjee, B. König, Eur. J. Org. Chem. 2020, 2020, 1193-1244;

I. K. Sideri, E. Voutyritsa, C. G. Kokotos, Org. Biomol. Chem. 2018, 16, 4596-4614.

W. Schilling, D. Riemer, Y. Zhang, N. Hatami, S. Das, ACS Catal. 2018, 8, 5425-5430;

H. Zhang, T. Guo, M. Wu, X. Huo, S. Tang, X. Wang, J. Liu, Tetrahedron Lett. 2021, 67, 152878;

S. Fukuzumi, K. Ohkubo, Chem. Sci. 2013, 4, 561-574;

F. Rusch, J.-C. Schober, M. Brasholz, ChemCatChem 2016, 8, 2881-2884;

N. F. Nikitas, D. I. Tzaras, I. Triandafillidi, C. G. Kokotos, Green Chem. 2020, 22, 471-477.

X. Zhang, K. P. Rakesh, L. Ravindar, H.-L. Qin, Green Chem. 2018, 20, 4790-4833.

C. L. Hill, Nature 1999, 401, 436-437;

A. B. Jones, J. Wang, A. T. Hamme II, W. Han, in Encyclopedia of Reagents for Organic Synthesis;

R. A. Sheldon, Chem. Commun. 2008, 3352-3365.

L. Xiong, J. Tang, Adv. Energy Mat. 2021, 11, 2003216.

L. Capaldo, D. Ravelli, Eur. J. Org. Chem. 2020, 2020, 2783-2806.

C. Gunanathan, D. Milstein, Science 2013, 341, 1229712;

Z. Chai, T.-T. Zeng, Q. Li, L.-Q. Lu, W.-J. Xiao, D. Xu, J. Am. Chem. Soc. 2016, 138, 10128-10131;

H. Fuse, H. Mitsunuma, M. Kanai, J. Am. Chem. Soc. 2020, 142, 4493-4499;

Z. Chai, Chem. Asian. J. 2021, 16, 460-473.

E. J. Horn, B. R. Rosen, Y. Chen, J. Tang, K. Chen, M. D. Eastgate, P. S. Baran, Nature 2016, 533, 77-81;

J. Liu, L. Lu, D. Wood, S. Lin, ACS Central Sci. 2020, 6, 1317-1340;

J. P. Barham, B. König, Angew. Chem. Int. Ed. 2020, 59, 11732-11747;

Angew. Chem. 2020, 132, 11828-11844;

L. Capaldo, L. L. Quadri, D. Ravelli, Angew. Chem. Int. Ed. 2019, 58, 17508-17510;

Angew. Chem. 2019, 131, 17670-17672.

K. Targos, O. P. Williams, Z. K. Wickens, J. Am. Chem. Soc. 2021, 143, 4125-4132.

E. Svobodová, R. Cibulka, in Flavin-Based Catalysis, 2021, pp. 265-291;

A. Rehpenn, A. Walter, G. Storch, Synthesis 2021, 53, 2583-2593;

J. B. Metternig, R. J. Mudd, G. R., in Photocatalysis in Organic Synthesis, 2019 ed. (Ed.: B. König), Georg Thieme Verlag, Stuttgart, 2019, pp. 391-404;

V. Srivastava, P. K. Singh, A. Srivastava, P. P. Singh, RSC Adv. 2021, 11, 14251-14259.

J. Immel, M. Chilamari, S. Bloom Chem. Sci. 2021, 12, 10083-10091;

A. H. Tolba, M. Krupička, J. Chudoba, R. Cibulka, Org. Lett. 2021, 23, 6825-6830;

T. Hartman, M. Reisnerová, J. Chudoba, E. Svobodová, N. Archipowa, R. J. Kutta, R. Cibulka, ChemPlusChem 2021, 86, 373-386;

A. H. Tolba, F. Vávra, J. Chudoba, R. Cibulka, Eur. J. Org. Chem. 2020, 2020, 1579-1585;

J. Gurruchaga-Pereda, V. Martínez-Martínez, E. Rezabal, X. Lopez, C. Garino, F. Mancin, A. L. Cortajarena, L. Salassa, ACS Catal. 2020, 10, 187-196;

H. Guo, H. Xia, X. Ma, K. Chen, C. Dang, J. Zhao, B. Dick, ACS Omega 2020, 5, 10586-10595;

L. M. Bouchet, A. A. Heredia, J. E. Argüello, L. C. Schmidt, Org. Lett. 2020, 22, 610-614.

A. Pokluda, Z. Anwar, V. Boguschová, I. Anusiewicz, P. Skurski, M. Sikorski, R. Cibulka, Adv. Synth. Catal. 2021, 363, 4371-4379;

J. Zelenka, R. Cibulka, J. Roithová, Angew. Chem. Int. Ed. 2019, 58, 15412-15420;

Angew. Chem. 2019, 131, 15558-15566.

A. Graml, T. Neveselý, R. Jan Kutta, R. Cibulka, B. König, Nat. Commun. 2020, 11, 3174;

T. Pavlovska, D. Král Lesný, E. Svobodová, I. Hoskovcová, N. Archipowa, R. J. Kutta, R. Cibulka, Chem. Eur. J. 2022, e202200768.

B. Cheng, B. König, in Flavin-Based Catalysis, 2021 (Cibulka R. and Fraaije M., Eds) pp. 245-264, .

D. S. Chung, S. H. Park, S.-G. Lee, H. Kim, Chem. Sci. 2021, 12, 5892-5897.

M. Uygur, J. H. Kuhlmann, M. C. Pérez-Aguilar, D. G. Piekarski, O. García Mancheño, Green Chem. 2021, 23, 3392-3399.

There are both flavin-based systems producing benzoic acids or their mixtures with aldehydes (ref. 17c, e or selectively aldehydes (see ref.24).

B. Mühldorf, R. Wolf, Chem. Commun. 2015, 51, 8425-8428;

C. Feldmeier, H. Bartling, K. Magerl, R. M. Gschwind, Angew. Chem. Int. Ed. 2015, 54, 1347-1351;

Angew. Chem. 2015, 127, 1363-1367.

T. Neveselý, E. Svobodová, J. Chudoba, M. Sikorski, R. Cibulka, Adv. Synth. Catal. 2016, 358, 1654-1663;

S. M. Bonesi, I. Manet, M. Freccero, M. Fagnoni, A. Albini, Chem. Eur. J. 2006, 12, 4844-4857;

E. Skolia, P. L. Gkizis, C. G. Kokotos, ChemPlusChem 2022, 87, e202200008;

E. Skolia, P. L. Gkizis, N. F. Nikitas, C. G. Kokotos, Green Chem. 2022, 24, 4108-4118.

M. Oliva, G. A. Coppola, E. V. Van der Eycken, U. K. Sharma, Adv. Synth. Catal. 2021, 363, 1810-1834.

U. Megerle, M. Wenninger, R.-J. Kutta, R. Lechner, B. König, B. Dick, E. Riedle, Phys. Chem. Chem. Phys. 2011, 13, 8869-8880.

ΔG is calculated from Rehm-Weller equation ΔG=Eox (substrate) − Ered (oxidant) −0.06; see ref.[30] for details.

A. N. Romero, D. A. Nicewicz, Chem. Rev. 2016, 116, 10075-10166.

D. C. Grills, S. V. Lymar, Phys. Chem. B 2022, 126, 262-269;

S. C. Doan, B. J. Schwartz, J. Phys. Chem. B 2013, 117, 4216-4221;

I. P. Bell, M. A. Rodgers, H. D. Burrows, J. Chem. Soc., Faraday Trans. 1 1977, 73, 315-326.

M. Neumeier, D. Sampedro, M. Májek, V. A. d. l. P. O′Shea, A. J. v. Wangelin, R. Pérez-Ruiz, Chem. Eur. J. 2018, 24, 105-108.

I. Ghosh, T. Ghosh, J. L. Bardagi, B. König, Science 2014, 346, 725-728;

I. A. MacKenzie, L. Wang, N. P. R. Onuska, O. F. Williams, K. Begam, A. M. Moran, B. D. Dunietz, D. A. Nicewicz, Nature 2020, 580, 76-80.

C. Greening, F. H. Ahmed, A. E. Mohamed, B. M. Lee, G. Pandey, A. C. Warden, C. Scott, J. G. Oakeshott, M. C. Taylor, C. J. Jackson, Microbiol. Mol. Biol. Rev. 2016, 80, 451-493;

M. Goldberg, I. Pecht, H. E. A. Kramer, R. Traber, P. Hemmerich, Biochim. Biophys. Acta - General Subjects 1981, 673, 570-593.

Y.-T. Kao, C. Saxena, T.-F. He, L. Guo, L. Wang, A. Sancar, D. Zhong, J. Am. Chem. Soc. 2008, 130, 13132-13139;

A. Sancar, Chem. Rev. 2003, 103, 2203-2238.

X. Gao, J. R. Turek-Herman, Y. J. Choi, R. D. Cohen, T. K. Hyster, J Am. Chem. Soc. 2021, 143, 19643-19647;

R. Foja, A. Walter, C. Jandl, E. Thyrhaug, J. Hauer, G. Storch, J. Am. Chem. Soc. 2022, 144, 4721-4726.

M. Krejčik, M. Daněk, F. Hartl, J. Electroanal. Chem. Interfac. Electrochem. 1991, 317, 179-187.

Introduction of flavin anions into photoredox catalysis: acid-base equilibria of lumichrome allow photoreductions with an anion of an elusive 10-unsubstituted isoalloxazine

A facile three-component route to powerful 5-aryldeazaalloxazine photocatalysts