Visible Light Photocatalysis of 2+2 Styrene Cycloadditions by Energy Transfer

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Citation: Zhan Lu, Tehshik Yoon (2012) Visible Light Photocatalysis of 2+2 Styrene Cycloadditions by Energy Transfer. Angewandte Chemie International Edition (Volume 51) (RSS)
DOI (original publisher): 10.1002/anie.201204835
Semantic Scholar (metadata): 10.1002/anie.201204835
Sci-Hub (fulltext): 10.1002/anie.201204835
Internet Archive Scholar (search for fulltext): Visible Light Photocatalysis of 2+2 Styrene Cycloadditions by Energy Transfer
Download: http://dx.doi.org/10.1002/anie.201204835
Tagged: Photochemistry (RSS)

Summary

The paper is about the prospects for the conduction of organic reactions that are useful for synthesis with visible light. The effort till now have been made in the direction of the study of photoredox properties of ruthenium and iridium polypyridyl complexes. The paper tend to discuss the numerous uses of carrying out organic reactions in visible light than in ultra-violet light like the lower cost, decreased energy requirements of visible light sources, no need of specialized photo reactors, etc. The paper discusses specially the visible light photocatalysis of cycloaddition reactions . In the paper, the photo-reduction and photo-oxidation reactions of Ru(bpy)3 2+ and the related ruthenium(II) chromophores to design [2+2], [3+2], and [4+2] cycloaddition reactions involving radical anion and radical cation intermediates are investigated. Although the diversity of products using this strategy is quite broad, the electron-transfer nature of these processes limit the scope of these reactions to either electron-rich and electron-deficient reactions that are agreeable to one-electron redox processes. Such electrochemical constraints will be important considerations in the design of any photoredox process, the paper explores the possibility of initiating similar transformations by energy transfer rather than by an electron- transfer mechanism. The results obtained are significant for numerous reasons. Firstly, the catalysis of reactions by energy transfer process upon irradiation with household visible light sources using the class of transition metal photocatalysts, that have recently come into limelight due to their ability to promote organic transformations by photoinduced electron transfer. Although the energy transfer cycloaddition is similar to the photoredox transformations, the scope of the reaction goes beyond the electrochemical properties of the substrates, and is instead governed by the relative excited state energies of the catalyst and styrenes. The findings suggest that the great number of organic reactions that were carried out in Ultra-violet light before can now be very well carried out in visible light.