Electrophotocatalytic Si-H Activation Governed by Polarity-Matching Effects

• Main Authors: Jiang, Y. (Author), Xu, K. (Author), Zeng, C. (Author)
• Format: Article
• Language: English
• Published: Chinese Chemical Society 2022
• Subjects: electrooxidation; electrophotocatalysis; LMCT; organic electrosynthesis
• Online Access: View Fulltext in Publisher

 Trialkylsilanes are important building blocks in organic synthesis; however, their widespread use in redox chemistry is limited by their high oxidation potentials and comparably high bond dissociation energies (BDEs) of Si-H and α-Si-C-H bonds (>92 kcal mol-1). Herein, we report a new strategy for Si-H bond homolysis enabled by the synergistic combination of electrooxidation, photoinduced ligand-to-metal charge transfer (LMCT), and radical-mediated hydrogen atom transfer (HAT). Governed by the polarity-matching effect, the HAT to electrophilic MeO or [Cl-OHCH3] from the more hydridic Si-H instead of a C-H bond allows the selective generation of silyl radicals. This electrophotocatalytic protocol provides rapid access to Si-functionalized benzimidazo-fused isoquinolinones with broad functional-group compatibility. Mechanistic studies have shown that n-Bu4NCl is essential to the electrooxidation of CeCl3 to form the Ce(IV) species. © 2022 CCS Chemistry.All right reserved.