- Email: [email protected]
Dearomative [4 + 2] Cycloaddition of Pyridine via Energy-Transfer Catalysis
without surgical treatment and only undergoing S1 (Figure 1E). The low toxicity of OTPA-TQ3 NPs was confirmed by cellular viability assays, hepatic and renal function analyses, and blood routine examination. Moreover, Tang et al. studied the influence of agent dose and found that a concentration of 650 mM could provide the most detailed information about tumors with little side effect. The authors developed a one-for-all molecular agent that can serve as powerful fluorescent probe, PA contrast agent, and Raman probe as needed, which give excellent performance in boosting the cancer surgery outcomes. Such function-transformable NP with controlled photophysical capabilities show unique merits over
other optical agents in terms of simply combining various components into one platform. A few challenges remain for the translation of this method. More in-depth pharmacokinetics and long-term toxicity tests, as well as nonxenograft tumor models for patients with metastases, should be explored to reinforce the authors’ conclusions. Overall, the study is a major step forward in the area of multi-modality organic imaging and is a noteworthy application of smart nanomaterials.
1. Wang, P., Fan, Y., Lu, L., Liu, L., Fan, L., Zhao, M., Xie, Y., Xu, C., and Zhang, F. (2018). NIR-II nanoprobes in-vivo assembly to improve image-guided surgery for metastatic ovarian cancer. Nat. Commun. 9, 2898. 2. Vahrmeijer, A.L., Hutteman, M., van der Vorst, J.R., van de Velde, C.J.H., and Frangioni, J.V. (2013). Image-guided cancer surgery using
near-infrared fluorescence. Nat. Rev. Clin. Oncol. 10, 507–518. 3. Feng, Z., Yu, X., Jiang, M., Zhu, L., Zhang, Y., Yang, W., Xi, W., Li, G., and Qian, J. (2019). Excretable IR-820 for in vivo NIR-II fluorescence cerebrovascular imaging and photothermal therapy of subcutaneous tumor. Theranostics 9, 5706–5719. 4. Steinberg, I., Huland, D.M., Vermesh, O., Frostig, H.E., Tummers, W.S., and Gambhir, S.S. (2019). Photoacoustic clinical imaging. Photoacoustics 14, 77–98. 5. Li, S., Chen, T., Wang, Y., Liu, L., Lv, F., Li, Z., Huang, Y., Schanze, K.S., and Wang, S. (2017). Conjugated polymer with intrinsic alkyne units for synergistically enhanced Raman imaging in living cells. Angew. Chem. Int. Ed. Engl. 56, 13455–13458. 6. Feng, G., and Liu, B. (2016). Multifunctional AIEgens for future theranostics. Small 12, 6528–6535. 7. Qi, J., Li, J., Liu, R., Li, Q., Zhang, H., Lam, J.W.Y., Kwok, R.T.K., Liu, D., Ding, D., and Tang, B.Z. (2019). Boosting fluorescencephotoacoustic-Raman properties in one fluorophore for precise cancer surgery. Chem 5, 2657–2677.
Preview
Dearomative [4 + 2] Cycloaddition of Pyridine via Energy-Transfer Catalysis Liang Chang,1 Yilin Chen,1 and Zhiwei Zuo1,* In this issue of Chem, Glorius and coworkers report the first photocatalytic dearomative cycloaddition of pyridine with alkene. High-value isoquinuclidines could be easily assembled from N-cinamoyl picolinamides under mild and operationally simple conditions. It seemed too good to be true that complex isoquinuclidines could be directly assembled from simple pyridines and alkenes via [4 + 2] cycloaddition. With the ever-increasing demand for the exploration of chemical space, the rapid construction of this type of complex molecule with a well-defined three-dimensional structure from feedstock chemicals has become an urgent need and a major driving force in the
synthetic community. The recent development of visible-light-induced energy-transfer catalysis, as depicted in Scheme 1, has enabled a major breakthrough in the dearomative cyclization of pyridine. As just reported in this issue of Chem by the Glorius group, a photocatalytic [4 + 2] cycloaddition that transfers N-cinnamoyl picolinamides into high-value isoquinuclidines under mild and operation-
2744 Chem 5, 2742–2750, November 14, 2019 ª 2019 Elsevier Inc.
ally simple conditions has been achieved, elegantly demonstrating the synthetic potential of visible-light photocatalysis in the construction of complex structures.1 Nitrogen-containing heterocycles have long been recognized as one of the most privileged structural manifolds in chemical synthesis because of their ubiquitous presence in natural products, approved pharmaceuticals, and preclinical chemical entities.2 Among the available synthetic strategies, catalytic dearomatization of aromatic heterocycles, such as indole and pyridine, has emerged as a rather effective and popular approach.3 Because of their availability in commercial sources and the modularity of the hexagonal
1School
of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China *Correspondence: [email protected] https://doi.org/10.1016/j.chempr.2019.10.020
such as Ir(dF(CF3)ppy)2(dtbpy(PF6) (60.8 kcal/mol). However, the triplet energy of pyridines (>70 kcal/mol) is relatively high in comparison with the light energy of blue-light photons (450 nm, 65 kcal/mol); thus, it is inaccessible by most photocatalysts, rendering pyridines energetically challenging substrates in this catalytic manifold. Accordingly, the photocatalytic dearomatization of pyridines has remained largely elusive.
Scheme 1. Dearomatization of Pyridines via Cycloaddition and Corresponding Accessible NHeterocyclic Compounds
framework, pyridine substrates have drawn significant research attention in this area. Over the last few decades, tremendous progress has been made in dearomative reductions and dearomative nucleophilic addition transformations,4 including the exciting development of the catalytic asymmetric dearomatization (CADA) of pyridine;5 nevertheless, the scope of the complexity of the generated products remains limited to the six-membered ring system. Utilizing pyridine to build up a bicyclic framework would provide intriguing opportunities to synthesize high-value scaffolds such as isoquinuclidine, yet it still remains a formidable challenge. The utilization of light energy for chemical activation not only allows reactions to be conducted under mild and sustainable conditions but also unlocks intriguing reactivity patterns to provide novel approaches for the construction of complex structures.6 The combina-
tion of photocatalysis and dearomatization has recently emerged as an exciting supplement to traditional strategies. The synthetic potential of this approach was first demonstrated by the Sarlah group in a two-step dearomative functionalization of benzenoid arenes.7 Elegantly, the You group8 and Glorius group9,10 each reported examples of [2 + 2] dearomative cycloadditions by utilizing visible-light energy transfer to activate indoles and naphthalenes for the facile access of strained cyclobutanes. This energy-transfer activation strategy was demonstrated to be rather straightforward and effective in these cases; nonetheless, it has not been applicable for pyridine substrates. Critically, the overall efficiency of energy transfer is correlated with the energy gap between the excited states of the donor (catalyst) and acceptor (substrate). The triplet state of electron-rich aromatics such as indoles and naphthalenes (55–60 kcal/mol) can be easily accessed by visible-light photocatalysts
To overcome this particular challenge, the Glorius group implemented alkene 1,2-biradical intermediates as an effective avenue to achieve catalytic dearomatization of pyridine, leading to the development of an operationally simple protocol for transferring easily accessible N-cinnamoyl picolinamides into high-value isoquinuclidine products. Utilizing a visible-light-induced energy-transfer strategy, the authors could effectively activate cinnamyl moieties into the triplet state (46 kcal/ mol), i.e., a highly reactive 1,2-biradical from a synthetic perspective. Through a clever reaction design, the biradical intermediate could undergo subsequent intramolecular cyclization with the pyridine moiety in a stepwise and highly selective manner to produce solely the desired [4 + 2] cycloaddition product. Under ambient reaction conditions, a variety of substitutions on the pyridine and cinnamyl moieties could be well tolerated, and excellent yields and selectivities were obtained across the board, providing rapid access to a diverse array of biologically relevant isoquinuclidines. Moreover, this efficient catalytic dearomatization reaction employed a polymer-immobilized Irbased photocatalyst, which could be recycled at least ten times without losing its efficiency, showcasing a sustainable and cost-competitive alternative to classic homogeneous catalysis. Significant mechanistic investigations and density functional theory (DFT) computational studies were performed
Chem 5, 2742–2750, November 14, 2019 2745
to rationalize the observed reactivity and selectivity. Notably, DFT calculations suggested that the tripletenergy transfer was thermodynamically favored in a comparison of the excited photocatalyst (ET = 60.8 kcal/mol) and cinnamyl moieties (ET = 45.846.5 kcal/mol). In this excited triplet intermediate, the a-carbonyl radical underwent a 5-exo-trig cyclization, and the resulting 1,6-biradical intermediate subsequently underwent radical-radical recombination to form bicyclic isoquinuclidines in a highly selective fashion. Regarding the cyclization pattern, it is worth noting that the dearomative [4 + 2] cycloaddition was, according to the DFT calculations, more favored than the [2 + 2] cycloaddition pathway from both the thermodynamic and kinetic points of view. Overall, this study by the Glorius group has provided a straightforward approach for the construction of a synthetically challenging isoquinuclidine scaffold. The use of ubiquitous alkenes and pyridines for rapid complexity construction, good compatibility between
commonly occurring functional groups, and the scalability of gram-scale reactions should certainly be embraced by the synthetic community. Moreover, the application of an energy-transfer strategy to enforce challenging dearomative cyclizations will continue to inspire exciting developments in synthetic chemistry.
ACKNOWLEDGMENTS Z.Z. acknowledges financial support from the National Natural Science Foundation of China (21772121 and 21971163). 1. Ma, J., Strieth-Kalthoff, F., Dalton, T., Freitag, M., Schwarz, J.L., Bergander, K., Daniliuc, C., and Glorius, F. (2019). Direct dearomatization of pyridines via an energy-transfer-catalyzed intramolecular [4 + 2] cycloaddition. Chem 5, this issue, 2854–2864. 2. Vitaku, E., Smith, D.T., and Njardarson, J.T. (2014). Analysis of the structural diversity, substitution patterns, and frequency of nitrogen heterocycles among U.S. FDA approved pharmaceuticals. J. Med. Chem. 57, 10257–10274. 3. Zheng, C., and You, S.-L. (2016). Catalytic asymmetric dearomatization by transitionmetal catalysis: a method for transformations of aromatic compounds. Chem 1, 830–857.
4. Remy, R., and Bochet, C.G. (2016). Arenealkene cycloaddition. Chem. Rev. 116, 9816– 9849. 5. Yang, Z.-P., Wu, Q.-F., Shao, W., and You, S.-L. (2015). Iridium-catalyzed intramolecular asymmetric allylic dearomatization reaction of pyridines, pyrazines, quinolines, and isoquinolines. J. Am. Chem. Soc. 137, 15899– 15906. 6. Strieth-Kalthoff, F., James, M.J., Teders, M., Pitzer, L., and Glorius, F. (2018). Energy transfer catalysis mediated by visible light: principles, applications, directions. Chem. Soc. Rev. 47, 7190–7202. 7. Southgate, E.H., Pospech, J., Fu, J., Holycross, D.R., and Sarlah, D. (2016). Dearomative dihydroxylation with arenophiles. Nat. Chem. 8, 922–928. 8. Zhu, M., Zheng, C., Zhang, X., and You, S.-L. (2019). Synthesis of cyclobutane-fused angular tetracyclic spiroindolines via visiblelight-promoted intramolecular dearomatization of indole derivatives. J. Am. Chem. Soc. 141, 2636–2644. 9. James, M.J., Schwarz, J.L., Strieth-Kalthoff, F., Wibbeling, B., and Glorius, F. (2018). Dearomative cascade photocatalysis: divergent synthesis through catalyst selective energy transfer. J. Am. Chem. Soc. 140, 8624– 8628. 10. Strieth-Kalthoff, F., Henkel, C., Teders, M., Kahnt, A., Knolle, W., Go´mez-Sua´rez, A., Dirian, K., Alex, W., Bergander, K., Daniliuc, C.G., et al. (2019). Discovery of unforeseen energy-transferbased transformations using a combined screening approach. Chem 5, 2183–2194.
Preview
Renewable Energy Nanosources for Sustainable Biomass Conversion
non, referred to as localized surface plasmon resonance (LSPR), indeed increases the electromagnetic field intensities around illuminated nanoparticles. This nanosource of energy can be harvested in many ways by neighboring functional nanostructures.
Vale´rie Caps1,*
It can be transferred to adsorbed molecules and transformed into vibrational energy, which has been exploited in detection and sensing applications. It can be
The use of light as a primary energy source in chemical transformations is one major pillar of the forthcoming energy transition. In this issue of Chem, Han et al. design a quite sophisticated antenna-reactor complex that selectively catalyzes the reductive cleavage of C–O bonds in aryl ethers under mild conditions. The interaction between light and matter has fascinated scientists for centuries. In particular, the collective oscillation of con-
duction electrons triggered by incident light in plasmonic nanoparticles has attracted much interest.1,2 This phenome-
2746 Chem 5, 2742–2750, November 14, 2019 ª 2019 Elsevier Inc.
1Institut de Chimie et Proce ´ de´s pour l’Energie, l’Environnement et la Sante´, CNRS UMR 7515, University of Strasbourg, 25 rue Becquerel, 67087 Strasbourg, France
*Correspondence: [email protected] https://doi.org/10.1016/j.chempr.2019.09.014
other optical agents in terms of simply combining various components into one platform. A few challenges remain for the translation of this method. More in-depth pharmacokinetics and long-term toxicity tests, as well as nonxenograft tumor models for patients with metastases, should be explored to reinforce the authors’ conclusions. Overall, the study is a major step forward in the area of multi-modality organic imaging and is a noteworthy application of smart nanomaterials.
1. Wang, P., Fan, Y., Lu, L., Liu, L., Fan, L., Zhao, M., Xie, Y., Xu, C., and Zhang, F. (2018). NIR-II nanoprobes in-vivo assembly to improve image-guided surgery for metastatic ovarian cancer. Nat. Commun. 9, 2898. 2. Vahrmeijer, A.L., Hutteman, M., van der Vorst, J.R., van de Velde, C.J.H., and Frangioni, J.V. (2013). Image-guided cancer surgery using
near-infrared fluorescence. Nat. Rev. Clin. Oncol. 10, 507–518. 3. Feng, Z., Yu, X., Jiang, M., Zhu, L., Zhang, Y., Yang, W., Xi, W., Li, G., and Qian, J. (2019). Excretable IR-820 for in vivo NIR-II fluorescence cerebrovascular imaging and photothermal therapy of subcutaneous tumor. Theranostics 9, 5706–5719. 4. Steinberg, I., Huland, D.M., Vermesh, O., Frostig, H.E., Tummers, W.S., and Gambhir, S.S. (2019). Photoacoustic clinical imaging. Photoacoustics 14, 77–98. 5. Li, S., Chen, T., Wang, Y., Liu, L., Lv, F., Li, Z., Huang, Y., Schanze, K.S., and Wang, S. (2017). Conjugated polymer with intrinsic alkyne units for synergistically enhanced Raman imaging in living cells. Angew. Chem. Int. Ed. Engl. 56, 13455–13458. 6. Feng, G., and Liu, B. (2016). Multifunctional AIEgens for future theranostics. Small 12, 6528–6535. 7. Qi, J., Li, J., Liu, R., Li, Q., Zhang, H., Lam, J.W.Y., Kwok, R.T.K., Liu, D., Ding, D., and Tang, B.Z. (2019). Boosting fluorescencephotoacoustic-Raman properties in one fluorophore for precise cancer surgery. Chem 5, 2657–2677.
Preview
Dearomative [4 + 2] Cycloaddition of Pyridine via Energy-Transfer Catalysis Liang Chang,1 Yilin Chen,1 and Zhiwei Zuo1,* In this issue of Chem, Glorius and coworkers report the first photocatalytic dearomative cycloaddition of pyridine with alkene. High-value isoquinuclidines could be easily assembled from N-cinamoyl picolinamides under mild and operationally simple conditions. It seemed too good to be true that complex isoquinuclidines could be directly assembled from simple pyridines and alkenes via [4 + 2] cycloaddition. With the ever-increasing demand for the exploration of chemical space, the rapid construction of this type of complex molecule with a well-defined three-dimensional structure from feedstock chemicals has become an urgent need and a major driving force in the
synthetic community. The recent development of visible-light-induced energy-transfer catalysis, as depicted in Scheme 1, has enabled a major breakthrough in the dearomative cyclization of pyridine. As just reported in this issue of Chem by the Glorius group, a photocatalytic [4 + 2] cycloaddition that transfers N-cinnamoyl picolinamides into high-value isoquinuclidines under mild and operation-
2744 Chem 5, 2742–2750, November 14, 2019 ª 2019 Elsevier Inc.
ally simple conditions has been achieved, elegantly demonstrating the synthetic potential of visible-light photocatalysis in the construction of complex structures.1 Nitrogen-containing heterocycles have long been recognized as one of the most privileged structural manifolds in chemical synthesis because of their ubiquitous presence in natural products, approved pharmaceuticals, and preclinical chemical entities.2 Among the available synthetic strategies, catalytic dearomatization of aromatic heterocycles, such as indole and pyridine, has emerged as a rather effective and popular approach.3 Because of their availability in commercial sources and the modularity of the hexagonal
1School
of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China *Correspondence: [email protected] https://doi.org/10.1016/j.chempr.2019.10.020
such as Ir(dF(CF3)ppy)2(dtbpy(PF6) (60.8 kcal/mol). However, the triplet energy of pyridines (>70 kcal/mol) is relatively high in comparison with the light energy of blue-light photons (450 nm, 65 kcal/mol); thus, it is inaccessible by most photocatalysts, rendering pyridines energetically challenging substrates in this catalytic manifold. Accordingly, the photocatalytic dearomatization of pyridines has remained largely elusive.
Scheme 1. Dearomatization of Pyridines via Cycloaddition and Corresponding Accessible NHeterocyclic Compounds
framework, pyridine substrates have drawn significant research attention in this area. Over the last few decades, tremendous progress has been made in dearomative reductions and dearomative nucleophilic addition transformations,4 including the exciting development of the catalytic asymmetric dearomatization (CADA) of pyridine;5 nevertheless, the scope of the complexity of the generated products remains limited to the six-membered ring system. Utilizing pyridine to build up a bicyclic framework would provide intriguing opportunities to synthesize high-value scaffolds such as isoquinuclidine, yet it still remains a formidable challenge. The utilization of light energy for chemical activation not only allows reactions to be conducted under mild and sustainable conditions but also unlocks intriguing reactivity patterns to provide novel approaches for the construction of complex structures.6 The combina-
tion of photocatalysis and dearomatization has recently emerged as an exciting supplement to traditional strategies. The synthetic potential of this approach was first demonstrated by the Sarlah group in a two-step dearomative functionalization of benzenoid arenes.7 Elegantly, the You group8 and Glorius group9,10 each reported examples of [2 + 2] dearomative cycloadditions by utilizing visible-light energy transfer to activate indoles and naphthalenes for the facile access of strained cyclobutanes. This energy-transfer activation strategy was demonstrated to be rather straightforward and effective in these cases; nonetheless, it has not been applicable for pyridine substrates. Critically, the overall efficiency of energy transfer is correlated with the energy gap between the excited states of the donor (catalyst) and acceptor (substrate). The triplet state of electron-rich aromatics such as indoles and naphthalenes (55–60 kcal/mol) can be easily accessed by visible-light photocatalysts
To overcome this particular challenge, the Glorius group implemented alkene 1,2-biradical intermediates as an effective avenue to achieve catalytic dearomatization of pyridine, leading to the development of an operationally simple protocol for transferring easily accessible N-cinnamoyl picolinamides into high-value isoquinuclidine products. Utilizing a visible-light-induced energy-transfer strategy, the authors could effectively activate cinnamyl moieties into the triplet state (46 kcal/ mol), i.e., a highly reactive 1,2-biradical from a synthetic perspective. Through a clever reaction design, the biradical intermediate could undergo subsequent intramolecular cyclization with the pyridine moiety in a stepwise and highly selective manner to produce solely the desired [4 + 2] cycloaddition product. Under ambient reaction conditions, a variety of substitutions on the pyridine and cinnamyl moieties could be well tolerated, and excellent yields and selectivities were obtained across the board, providing rapid access to a diverse array of biologically relevant isoquinuclidines. Moreover, this efficient catalytic dearomatization reaction employed a polymer-immobilized Irbased photocatalyst, which could be recycled at least ten times without losing its efficiency, showcasing a sustainable and cost-competitive alternative to classic homogeneous catalysis. Significant mechanistic investigations and density functional theory (DFT) computational studies were performed
Chem 5, 2742–2750, November 14, 2019 2745
to rationalize the observed reactivity and selectivity. Notably, DFT calculations suggested that the tripletenergy transfer was thermodynamically favored in a comparison of the excited photocatalyst (ET = 60.8 kcal/mol) and cinnamyl moieties (ET = 45.846.5 kcal/mol). In this excited triplet intermediate, the a-carbonyl radical underwent a 5-exo-trig cyclization, and the resulting 1,6-biradical intermediate subsequently underwent radical-radical recombination to form bicyclic isoquinuclidines in a highly selective fashion. Regarding the cyclization pattern, it is worth noting that the dearomative [4 + 2] cycloaddition was, according to the DFT calculations, more favored than the [2 + 2] cycloaddition pathway from both the thermodynamic and kinetic points of view. Overall, this study by the Glorius group has provided a straightforward approach for the construction of a synthetically challenging isoquinuclidine scaffold. The use of ubiquitous alkenes and pyridines for rapid complexity construction, good compatibility between
commonly occurring functional groups, and the scalability of gram-scale reactions should certainly be embraced by the synthetic community. Moreover, the application of an energy-transfer strategy to enforce challenging dearomative cyclizations will continue to inspire exciting developments in synthetic chemistry.
ACKNOWLEDGMENTS Z.Z. acknowledges financial support from the National Natural Science Foundation of China (21772121 and 21971163). 1. Ma, J., Strieth-Kalthoff, F., Dalton, T., Freitag, M., Schwarz, J.L., Bergander, K., Daniliuc, C., and Glorius, F. (2019). Direct dearomatization of pyridines via an energy-transfer-catalyzed intramolecular [4 + 2] cycloaddition. Chem 5, this issue, 2854–2864. 2. Vitaku, E., Smith, D.T., and Njardarson, J.T. (2014). Analysis of the structural diversity, substitution patterns, and frequency of nitrogen heterocycles among U.S. FDA approved pharmaceuticals. J. Med. Chem. 57, 10257–10274. 3. Zheng, C., and You, S.-L. (2016). Catalytic asymmetric dearomatization by transitionmetal catalysis: a method for transformations of aromatic compounds. Chem 1, 830–857.
4. Remy, R., and Bochet, C.G. (2016). Arenealkene cycloaddition. Chem. Rev. 116, 9816– 9849. 5. Yang, Z.-P., Wu, Q.-F., Shao, W., and You, S.-L. (2015). Iridium-catalyzed intramolecular asymmetric allylic dearomatization reaction of pyridines, pyrazines, quinolines, and isoquinolines. J. Am. Chem. Soc. 137, 15899– 15906. 6. Strieth-Kalthoff, F., James, M.J., Teders, M., Pitzer, L., and Glorius, F. (2018). Energy transfer catalysis mediated by visible light: principles, applications, directions. Chem. Soc. Rev. 47, 7190–7202. 7. Southgate, E.H., Pospech, J., Fu, J., Holycross, D.R., and Sarlah, D. (2016). Dearomative dihydroxylation with arenophiles. Nat. Chem. 8, 922–928. 8. Zhu, M., Zheng, C., Zhang, X., and You, S.-L. (2019). Synthesis of cyclobutane-fused angular tetracyclic spiroindolines via visiblelight-promoted intramolecular dearomatization of indole derivatives. J. Am. Chem. Soc. 141, 2636–2644. 9. James, M.J., Schwarz, J.L., Strieth-Kalthoff, F., Wibbeling, B., and Glorius, F. (2018). Dearomative cascade photocatalysis: divergent synthesis through catalyst selective energy transfer. J. Am. Chem. Soc. 140, 8624– 8628. 10. Strieth-Kalthoff, F., Henkel, C., Teders, M., Kahnt, A., Knolle, W., Go´mez-Sua´rez, A., Dirian, K., Alex, W., Bergander, K., Daniliuc, C.G., et al. (2019). Discovery of unforeseen energy-transferbased transformations using a combined screening approach. Chem 5, 2183–2194.
Preview
Renewable Energy Nanosources for Sustainable Biomass Conversion
non, referred to as localized surface plasmon resonance (LSPR), indeed increases the electromagnetic field intensities around illuminated nanoparticles. This nanosource of energy can be harvested in many ways by neighboring functional nanostructures.
Vale´rie Caps1,*
It can be transferred to adsorbed molecules and transformed into vibrational energy, which has been exploited in detection and sensing applications. It can be
The use of light as a primary energy source in chemical transformations is one major pillar of the forthcoming energy transition. In this issue of Chem, Han et al. design a quite sophisticated antenna-reactor complex that selectively catalyzes the reductive cleavage of C–O bonds in aryl ethers under mild conditions. The interaction between light and matter has fascinated scientists for centuries. In particular, the collective oscillation of con-
duction electrons triggered by incident light in plasmonic nanoparticles has attracted much interest.1,2 This phenome-
2746 Chem 5, 2742–2750, November 14, 2019 ª 2019 Elsevier Inc.
1Institut de Chimie et Proce ´ de´s pour l’Energie, l’Environnement et la Sante´, CNRS UMR 7515, University of Strasbourg, 25 rue Becquerel, 67087 Strasbourg, France
*Correspondence: [email protected] https://doi.org/10.1016/j.chempr.2019.09.014