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Araujo Dias AJ, Muranaka A, Uchiyama M, Tanaka K, Nagashima Y. Vibration-mediated long-wavelength photolysis of electronegative bonds beyond S 0-S 1 and S 0-T 1 transitions. Commun Chem 2024; 7:126. [PMID: 38834838 DOI: 10.1038/s42004-024-01208-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Accepted: 05/21/2024] [Indexed: 06/06/2024] Open
Abstract
Photolysis is an attractive method in organic synthesis to produce free radicals through direct bond cleavage. However, in this method, specific irradiation wavelengths of light have been considered indispensable for excitation through S0-Sn or S0-Tn transitions. Here we report the photoinduced homolysis of electronegative interelement bonds using light at wavelengths much longer than theoretically and spectroscopically predicted for the S0-Sn or S0-Tn transitions. This long-wavelength photolysis proceeds in N-Cl, N-F, and O-Cl bonds at room temperature under blue, green, and red LED irradiation, initiating diverse radical reactions. Through experimental, spectroscopic, and computational studies, we propose that this "hidden" absorption is accessible via electronic excitations from naturally occurring vibrationally excited ground states to unbonded excited states and is due to the electron-pair repulsion between electronegative atoms.
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Affiliation(s)
- Antônio Junio Araujo Dias
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, 152-8550, Japan
| | - Atsuya Muranaka
- Molecular Structure Characterization Unit, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Masanobu Uchiyama
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Ken Tanaka
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, 152-8550, Japan.
| | - Yuki Nagashima
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, 152-8550, Japan.
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Nakajima M, Nagasawa S, Yamazaki K, Yazawa T, Yoneyama H, Kotaka Y, Nemoto T. Direct S 0 → T n Transition under Visible Light Irradiation Enabling Synthesis of a Pseudoindoxyl Scaffold. Org Lett 2024; 26:3289-3293. [PMID: 38568017 DOI: 10.1021/acs.orglett.4c00957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2024]
Abstract
Pseudoindoxyl is a partial skeleton found in various natural products. Its light-absorption properties make it useful for the design of functional molecules. However, versatile synthesis methods have not yet been reported. In this report, we present a versatile synthetic method for pseudoindoxyls using the direct S0 → Tn transition under visible light irradiation. We also discuss the application of pseudoindoxyls as photocatalysts.
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Affiliation(s)
- Masaya Nakajima
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8675, Japan
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Sho Nagasawa
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Keita Yamazaki
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Tomohiro Yazawa
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Honoka Yoneyama
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Yuko Kotaka
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8675, Japan
| | - Tetsuhiro Nemoto
- Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1, Inohana, Chuo-ku, Chiba 260-8675, Japan
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Hoving M, Haaksma JJ, Stoppel A, Chronc L, Hoffmann J, Beil SB. Triplet Energy Transfer Mechanism in Copper Photocatalytic N- and O-Methylation. Chemistry 2024; 30:e202400560. [PMID: 38363220 DOI: 10.1002/chem.202400560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 02/15/2024] [Accepted: 02/16/2024] [Indexed: 02/17/2024]
Abstract
Methylation reactions are chemically simple but challenging to perform under mild and non-toxic conditions. A photochemical energy transfer strategy was merged with copper catalysis to enable fast reaction times of minutes and broad applicability to N-heterocycles, (hetero-)aromatic carboxylic acids, and drug-like molecules in high yields and good functional group tolerance. Detailed mechanistic investigations, using kinetic analysis, aprotic MS, UV/Vis, and luminescence quenching experiments revealed a triplet-triplet energy transfer mechanism between hypervalent iodine(III) reagents and readily available photosensitizers.
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Affiliation(s)
- Martijn Hoving
- Stratingh Institute for Chemistry, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Jacob-Jan Haaksma
- Stratingh Institute for Chemistry, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Anne Stoppel
- Stratingh Institute for Chemistry, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Lukas Chronc
- Stratingh Institute for Chemistry, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Jonas Hoffmann
- Stratingh Institute for Chemistry, University of Groningen, 9747 AG, Groningen, The Netherlands
| | - Sebastian B Beil
- Stratingh Institute for Chemistry, University of Groningen, 9747 AG, Groningen, The Netherlands
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