Electron-Donor–Acceptor Enabled Electrophilic C(sp2)-C(sp3) Cross-Coupling

Abstract

The construction of C(sp2)-C(sp3) bonds is fundamental to pharmaceutical synthesis, yet metal-free approaches to electrophilic cross-coupling remain underdeveloped. Herein, we report a visible-light-driven, metal-free cross-coupling between heteroaryl nitriles and alkyl bromides enabled by a rationally designed aminosilane, (TMS)3SiNHPh. This reagent engages electron-deficient nitriles in an EDA complex via π–π interaction. Photoinduced electron transfer generates a silyl radical that triggers XAT from alkyl bromides, delivering alkyl radicals for subsequent decyanative coupling without the need for an external photocatalyst or transition-metal catalyst. The method accommodates a broad range of substrates, providing alkylated heteroarenes in moderate to good yields, and extends to Minisci-type C–H alkylations, underscoring the versatility of this platform. This work demonstrates that strategic EDA donor design can address a long-standing challenge in metal-free electrophilic coupling.