A large number of reagents have been developed for the synthesis of trifluoromethylated compounds. However, an ongoing challenge in trifluoromethylation reaction is the use of less expensive and practical trifluoromethyl sources. We report herein the unprecedented direct trifluoromethylation of (hetero)arenes using trifluoromethanesulfonic anhydride as a radical trifluoromethylation reagent by merging photoredox catalysis and pyridine activation. Furthermore, introduction of both the CF and OTf groups of the trifluoromethanesulfonic anhydride into internal alkynes to access tetrasubstituted trifluoromethylated alkenes was achieved. Since trifluoromethanesulfonic anhydride is a low-cost and abundant chemical, this method provides a cost-efficient and practical route to trifluoromethylated compounds.
The transformation of a large‐volume industrial by‐product and stable greenhouse gas fluoroform (HCF3) to useful products has recently received significant attention. Now, a simple and scalable preparation of AgCF3 by treatment of HCF3 with t‐BuOK and AgOAc is disclosed. The reactivity of the HCF3‐derived AgCF3 has been demonstrated by hydrotrifluoromethylation of alkenes and C−H trifluoromethylation of (hetero)arenes. This work not only provides a new avenue for the utilization of HCF3, but also presents a reliable and easy‐to‐execute synthesis of the relatively stable AgCF3 solution.
Biocatalysis has revolutionized chemical synthesis, providing sustainable methods for preparing various organic molecules. In enzyme-mediated organic synthesis, most reactions involve molecules operating from their ground states. Over the past 25 years, there has been an increased interest in enzymatic processes that utilize electronically excited states accessed through photoexcitation. These photobiocatalytic processes involve a diverse array of reaction mechanisms that are complementary to one another. This comprehensive review will describe the state-of-the-art strategies in photobiocatalysis for organic synthesis until December 2022. Apart from reviewing the relevant literature, a central goal of this review is to delineate the mechanistic differences between the general strategies employed in the field. We will organize this review based on the relationship between the photochemical step and the enzymatic transformations. The review will include mechanistic studies, substrate scopes, and protein optimization strategies. By clearly defining mechanisticallydistinct strategies in photobiocatalytic chemistry, we hope to illuminate future synthetic opportunities in the area.
An ongoing challenge in trifluoromethylthiolation reactions is the use of less expensive and easily available trifluoromethylthio sources. Herein, we disclose an unprecedented usage of trifluoromethanesulfonic anhydride (Tf2O) as a radical trifluoromethylthiolating reagent. Hydrotrifluoromethylthiolation of unactivated alkenes and alkynes with Tf2O in the presence of PMePh2 and H2O under visible‐light photoredox catalysis gave the addition products. The trifluoromethylthio radical (.SCF3) was first formed from Tf2O through a photoredox radical processes and deoxygenative reduction of PMePh2, and H2O serves as the H‐atom donor for the hydrotrifluoromethylthiolation reaction. This reaction provides a new strategy for radical trifluoromethylthiolation.
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