Site-Selective Electrochemical C–H Silylations of Pyridines Enabled by Temporary Reductive Dearomatization

Site-selective pyridine C-H silylation chemistry is of significant value but remains underdeveloped. In this study, we demonstrated that electron-deficient pyridines are highly selectively reductively silylated at the C4-position under electrochemical reduction conditions. A diverse array of C4-silylated pyridines was synthesized in good-to-excellent yields using common chlorosilanes as activating agents. Additionally, the use of bulky chlorosilanes led to the formation of the C5-silylated products, albeit in moderate yields. This method is noteworthy due to its mild reaction conditions, simplicity, and excellent site selectivities for a diverse range of pyridines. Site-selective silylations of electron-deficient pyridines is presented, the C4-to-C5 selectivity can be controlled by adjusting the bulkiness of the chlorosilanes.