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Updated: Oct 26, 2025
![Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F60786.jpg&w=3840&q=50)
Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
Published on: July 17, 2020
Turning the Light on Phenols: New Opportunities in Organic Synthesis
Beatrice Bartolomei1, Giuseppe Gentile1, Cristian Rosso1
1Department of Chemical and Pharmaceutical Sciences, INSTM UdR, University of Trieste, Via Licio Giorgieri 1, Trieste, 34127, Italy.
Abstract:
Phenols (I) are extremely relevant chemical functionalities in natural, synthetic and industrial chemistry. Their corresponding electron-rich anions, namely phenolates (I), are characterized by interesting physicochemical properties that can be drastically altered upon light excitation. Specifically, phenolates (I) become strong reducing agents in the excited state and are able to generate reactive radicals from suitable precursors via single-electron transfer processes. Thus, these species can photochemically trigger strategic bond-forming reactions, including their direct aromatic C-H functionalization. Moreover, substituted phenolate anions can act as photocatalysts to enable synthetically useful organic transformations. An alternative mechanistic manifold is represented by the ability of phenolate derivatives I to form ground state electron donor-acceptor (EDA) complexes with electron-poor radical sources. These complementary scenarios have paved the way for the development of a wide range of relevant organic reactions. In this Minireview, we present the main examples of this research field, and give insight on emerging trends in phenols photocatalysis towards richer organic synthesis.
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