Photoinduced Single‐Electron Transfer as an Enabling Principle in the Radical Borylation of Alkenes with NHC–Borane

• Published in: Angewandte Chemie International Edition Vol. 59; no. 17; pp. 6706 - 6710
• Main Authors: Xia, Peng‐Ju, Song, Dan, Ye, Zhi‐Peng, Hu, Yuan‐Zhuo, Xiao, Jun‐An, Xiang, Hao‐Yue, Chen, Xiao‐Qing, Yang, Hua
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 20-04-2020
• Edition: International ed. in English
• Subjects: Alkenes; Boranes; borylation; Electron transfer; Hydrogen bonds; Initiators; NHC–boranes; photocatalysis; single electron transfer; NHC-boranes; alkenes; photocatalysis; single electron transfer; borylation
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201913398

A photoinduced SET process enables the direct B−H bond activation of NHC–boranes. In contrast to common hydrogen atom transfer (HAT) strategies, this photoinduced reaction simply takes advantage of the beneficial redox potentials of NHC–boranes, thus obviating the need for extra radical initiators. The resulting NHC–boryl radical was used for the borylation of a wide range of α‐trifluoromethylalkenes and alkenes with diverse electronic and structural features, providing facile access to highly functionalized borylated molecules. Labeling and photoquenching experiments provide insight into the mechanism of this photoinduced SET pathway.
A photoinduced SET process enables the direct B−H bond activation of NHC–boranes. The resulting NHC–boryl radical was used for the borylation of a wide range of α‐trifluoromethylalkenes and alkenes with diverse electronic and structural features, providing facile access to highly functionalized borylated molecules.