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  • Perspective
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Visible light photocatalysis as a greener approach to photochemical synthesis

Abstract

Light can be considered an ideal reagent for environmentally friendly, 'green' chemical synthesis; unlike many conventional reagents, light is non-toxic, generates no waste, and can be obtained from renewable sources. Nevertheless, the need for high-energy ultraviolet radiation in most organic photochemical processes has limited both the practicality and environmental benefits of photochemical synthesis on industrially relevant scales. This Perspective describes recent approaches to the use of metal polypyridyl photocatalysts in synthetic organic transformations. Given the remarkable photophysical properties of these complexes, these new transformations, which use Ru(bpy)32+ and related photocatalysts, can be conducted using almost any source of visible light, including both store-bought fluorescent light bulbs and ambient sunlight. Transition metal photocatalysis thus represents a promising strategy towards the development of practical, scalable industrial processes with great environmental benefits.

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Figure 1: Oxidative and reductive quenching cycles in Ru(bpy)32+ photochemistry.
Figure 2: Photocatalytic [2+2] cycloadditions using visible light irradiation.
Figure 3: Merged organocatalytic and photocatalytic reactions.
Figure 4: Other recent approaches to transition metal photoredox catalysis in synthetic transformations.

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References

  1. Morton, O. Silicon Valley sunrise. Nature 443, 19–22 (2006).

    Article  CAS  Google Scholar 

  2. Nocera, D. G. On the future of global energy. Daedalus 135, 112–115 (2006).

    Article  Google Scholar 

  3. Lewis, N. S. Toward cost-effective solar energy use. Science 315, 798–801 (2007).

    Article  CAS  Google Scholar 

  4. Roth, H. D. The beginnings of organic photochemistry. Angew. Chem. Int. Ed. Engl. 28, 1193–1207 (1989).

    Article  Google Scholar 

  5. Albini, A. & Fagnoni, M. Green chemistry and photochemistry were born at the same time. Green Chem. 6, 1–6 (2004).

    Article  CAS  Google Scholar 

  6. Albini, A. & Fagnoni, M. 1908: Giacomo Ciamician and the concept of green chemistry. ChemSusChem 1, 63–66 (2008).

    Article  CAS  Google Scholar 

  7. Ciamician, G. The photochemistry of the future. Science 36, 385–394 (1912).

    Article  CAS  Google Scholar 

  8. Fagnoni, M., Dondi, D., Ravelli, D. & Albini, A. Photocatalysis for the formation of the C–C bond. Chem. Rev. 107, 2725–2756 (2007).

    Article  CAS  Google Scholar 

  9. Protti, S. & Fagnoni, M. The sunny side of chemistry: Green synthesis by solar light. Photochem. Photobiol. Sci. 8, 1499–1516 (2009).

    Article  CAS  Google Scholar 

  10. Oelgemöller, M., Jung, C. & Mattay, J. Green photochemistry: Production of fine chemicals with sunlight. Pure Appl. Chem. 79, 1939–1947 (2007).

    Article  Google Scholar 

  11. Esser, P., Pohlmann, B. & Scharf, H.-D. The photochemical synthesis of fine chemicals with sunlight. Angew. Chem. Int. Ed. Engl. 33, 2009–2023 (1994).

    Article  Google Scholar 

  12. Lewis, N. S. & Nocera, D. G. Powering the planet: Chemical challenges in solar energy utilization. Proc. Natl Acad. Sci. USA 103, 15729–15735 (2006).

    Article  CAS  Google Scholar 

  13. Balzani, V., Credi, A. & Venturi, M. Photochemical conversion of solar energy. ChemSusChem 1, 26–58 (2008).

    Article  CAS  Google Scholar 

  14. Kalyanasundaram, K. Photophysics, photochemistry, and solar energy conversion with tris(bipyridyl)ruthenium(II) and its analogues. Coord. Chem. Rev. 46, 159–244 (1982).

    Article  CAS  Google Scholar 

  15. Juris, A., Balzani, V., Barigelletti, F., Campagna, S., Belser, P. & von Zelewsky, A. Ru(II) polypyridine complexes: Photophysics, photochemistry, electrochemistry, and chemiluminescence. Coord. Chem. Rev. 84, 85–277 (1988).

    Article  CAS  Google Scholar 

  16. Kalyanasundaram, K. in Photochemistry of Polypyridine and Porphyrin Complexes 339–368 (Academic Press, 1992).

    Google Scholar 

  17. Ischay, M. A., Anzovino, M. E., Du, J. & Yoon, T. P. Efficient visible light photocatalysis of [2+2] enone cycloadditions. J. Am. Chem. Soc. 130, 12886–12887 (2008).

    Article  CAS  Google Scholar 

  18. Nicewicz, D. A. & MacMillan, D. W. C. Merging photoredox catalysis with organocatalysis: The direct asymmetric alkylation of aldehydes. Science 3 22, 77–80 (2008).

    Article  Google Scholar 

  19. Cano-Yelo, H. & Deronzier, A. Photocatalysis of the Pschorr reaction by tris-(2,2′-bipyridyl)ruthenium(II) in the phenanthrene series. J. Chem. Soc. Perkin Trans. 2 1093–1098 (1984).

  20. Cano-Yelo, H. & Deronzier, A. Photo-oxidation of some carbinols by the Ru(II) polypyridyl complex-aryl diazonium salt system. Tetrahedron Lett. 2 5, 5517–5520 (1984).

    Article  Google Scholar 

  21. Zen, J.-M., Liou, S.-L., Kumar, A. S. & Hsia, M.-S. An efficient and selective photocatalytic system for the oxidation of sulfides to sulfoxides. Angew. Chem. Int. Ed. 42, 577–579 (2003).

    Article  CAS  Google Scholar 

  22. Burstall, F. H. Optical activity dependent on co-ordinated bivalent ruthenium. J. Chem. Soc. 173–175 (1936).

  23. Demas, J. N. & Crosby, G. A. Quantum efficiencies on transition metal complexes. II. Charge-transfer luminescence. J. Am. Chem. Soc. 93, 2841–2847 (1971).

    Article  Google Scholar 

  24. Kalyanasundaram, K., Kiwi, J. & Grätzel, M. Hydrogen evolution from water by visible light, a homogeneous three component test system for redox catalysis. Helv. Chim. Acta 61, 2720–2730 (1978).

    Article  CAS  Google Scholar 

  25. Brown, G. M., Brunschwig, B. S., Creutz, C., Endicott, J. F. & Sutin, N. Homogeneous catalysis of the photoreduction of water by visible light. Mediation by a tris(2,2′-bipyridine)ruthenium(II)-cobalt(II) macrocycle system. J. Am. Chem. Soc. 101, 1298–1300 (1979).

    Article  CAS  Google Scholar 

  26. Crimmins, M. T. Synthetic applications of intramolecular enone-olefin photocycloadditions. Chem. Rev. 88, 1453–1473 (1988).

    Article  CAS  Google Scholar 

  27. Bach, T. Stereoselective intermolecular [2+2]-photocycloaddition reactions and their application in synthesis. Synthesis 683–708 (1998).

  28. Baik, T.-G., Luiz, A. L., Wang, L.-C. & Krische, M. J. A diastereoselective metal-catalyzed [2+2] cycloaddition of bis-enones. J. Am. Chem. Soc. 123, 6716–6717 (2001).

    Article  CAS  Google Scholar 

  29. Roh, Y., Jang, H.-Y., Lynch, V., Bauld, N. L. & Krische, M. J. Anion radical chain cycloaddition of tethered enones: Intramolecular cyclobutanation and Diels−Alder cycloaddition. Org. Lett. 4, 611–613 (2002).

    Article  CAS  Google Scholar 

  30. Yang, J., Felton, G. A. N., Bauld, N. L. & Krische, M. J. chemically induced anion radical cycloadditions: Intramolecular cyclobutanation of bis(enones) via homogeneous electron transfer. J. Am. Chem. Soc. 126, 1634–1635 (2004).

    Article  CAS  Google Scholar 

  31. Fournier, F. & Fournier, M. Transferts d'électrons assistés par les métaux de transition: influence de la nature du cation métallique sur la réduction de composés carbonylés en milieu aprotique. Can. J. Chem. 64, 881–890 (1986).

    Article  CAS  Google Scholar 

  32. House, H. O., Huber, L. E. & Umen, M. J. Empirical rules for estimating the reduction potential of α, β-unsaturated carbonyl compounds. J. Am. Chem. Soc. 94, 8471–8475 (1972).

    Article  CAS  Google Scholar 

  33. Du, J. & Yoon, T. P. Crossed intermolecular [2+2] cycloadditions of acyclic enones via visible light photocatalysis. J. Am. Chem. Soc. 131, 14604–14605 (2009).

    Article  CAS  Google Scholar 

  34. MacMillan, D. W. C. The advent and development of organocatalysis. Nature 455, 304–308 (2008).

    Article  CAS  Google Scholar 

  35. Beeson, T. D., Mastracchio, A., Hong, J., Ashton, K. & MacMillan, D. W. C. Enantioselective organocatalysis using SOMO activation. Science 3 16, 582–585 (2007).

    Article  Google Scholar 

  36. Nagib, D. A., Scott, M. E. & MacMillan, D. W. C. Enantioselective α-trifluoromethylation of aldehydes via photoredox organocatalysis. J. Am. Chem. Soc. 131, 10875–10877 (2009).

    Article  CAS  Google Scholar 

  37. Slinker, J. D. et al. Efficient yellow electroluminescence from a single layer of a cyclometalated iridium complex. J. Am. Chem. Soc. 1 26, 2763–2767 (2004).

    Article  Google Scholar 

  38. Flamigni, L., Barbieri, A., Sabatini, C., Ventura, B. & Barigelletti, F. Photochemistry and photophysics of coordination compounds: Iridium. Top. Curr. Chem. 281, 143–203 (2007).

    Article  CAS  Google Scholar 

  39. Hagmann, W. K. The many roles for fluorine in medicinal chemistry. J. Med. Chem. 51, 4359–4369 (2008).

    Article  CAS  Google Scholar 

  40. Purser, S., Moore, P. R., Swallow, S. & Gouverneur, V. Fluorine in medicinal chemistry. Chem. Soc. Rev. 37, 320–330 (2008).

    Article  CAS  Google Scholar 

  41. Zeitler, K. Photoredox catalysis with visible light. Angew. Chem. Int. Ed. 4 8, 9785–9789 (2009).

    Article  Google Scholar 

  42. Narayanam, J. M. R., Tucker, J. W. & Stephenson, C. R. J. Electron-transfer photoredox catalysis: Development of a tin-free reductive dehalogenation reaction. J. Am. Chem. Soc. 131, 8756–8757 (2009).

    Article  CAS  Google Scholar 

  43. Tucker, J. W., Narayanam, J. M. R., Krabbe, S. W. & Stephenson, C. R. J. Electron transfer photoredox catalysis: Intramolecular radical addition to indoles and pyrroles. Org. Lett. 12, 368–371 (2010).

    Article  CAS  Google Scholar 

  44. Koike, T. & Akita, M. Photoinduced oxyamination of enamines and aldehydes with TEMPO catalyzed by [Ru(bpy)3]2+. Chem. Lett. 38, 166–167 (2009).

    Article  CAS  Google Scholar 

  45. Ferrere, S. & Gregg, B. A. Photosensitization of TiO2 by [FeII(2,2′-bipyridine-4,4′-dicarboxylic acid)2(CN)2]: Band selective electron injection from ultra-short-lived excited states. J. Am. Chem. Soc. 120, 843–844 (1998).

    Article  CAS  Google Scholar 

  46. Green, O., Gandhi, B. A. & Burstyn, J. N. Photophysical characteristics and reactivity of bis(2,9-di-tert-butyl-1,10-phenanthroline)copper(I). Inorg. Chem. 48, 5704–5714 (2009).

    Article  CAS  Google Scholar 

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Acknowledgements

Research concerning the photocatalytic [2+2] cycloadditions described in this Perspective was supported by a Research Corporation Cottrell Scholar Award, a Beckman Young Investigator Award, and a Fellowship from the Sloan Foundation.

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Correspondence to Tehshik P. Yoon.

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Yoon, T., Ischay, M. & Du, J. Visible light photocatalysis as a greener approach to photochemical synthesis. Nature Chem 2, 527–532 (2010). https://doi.org/10.1038/nchem.687

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