Electron-Donor-Acceptor Enabled Electrophilic C(sp2)‑C(sp3) Cross-Coupling
Zheng Wang1, Xiaodong Qiu1, Burkhard König1
1Fakultät für Chemie und Pharmazie, Universität Regensburg, 93040 Regensburg, Germany.
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.
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