Photocatalytic C–H silylation of heteroarenes by using trialkylhydrosilanes

Abstract

The efficient and selective C-H silylation of heteroarenes, especially the pharmaceutically relevant electron-deficient heteroarenes, represents a great challenge in organic synthesis. Herein we wish to report a distinctive visible light-promoted photocatalytic C-H silylation approach that enables the direct coupling of trialkylhydrosilanes with both electron-deficient and -rich heteroarenes as well as with cyano-substituted arenes in moderate to high yields and with good regioselectivity. The protocol features operational simplicity, mild reaction conditions, and the use of safe and readily available Na₂S₂O₈, bis(trimethylsilyl) peroxide (BTMSPO) or ⁱPr₃SiSH as the radical initiators. Notably, the challenging bulky and inert trialkylhydrosilanes, such as (<i>t</i>-butyldimethyl)silane ( ^<i>t</i> BuMe₂SiH) and (triisopropyl)silane (ⁱPr₃SiH), work smoothly with the protocol. Moreover, despite the higher stability of ^<i>t</i> BuMe₂Si silylation products, our studies revealed their great reactivity and versatility in diverse C-Si-based chemical transformations, providing an operationally simple, low-cost, and environmentally benign synthetic technology for molecule construction and elaboration.