Alkynyl-Germanium Architectures Through Electrochemical Low-Valent Iron-Catalyzed Conjunctive Coupling

Catalytic cross-coupling by transition metals has transformed carbon-germanium (C─Ge) bond formation in organic synthesis. The formation of unsaturated C(sp)─Ge bonds, however, remains a largely uncharted frontier. We herein report the construction of congested alkynyl-germane architectures via iron-catalyzed coupling of alkynyl chlorides with chlorogermanes, affording a broad spectrum of germane products. The methodology also enables late-stage functionalization of natural products and drug-derived molecules bearing C(sp)─Ge bonds, thereby demonstrating its synthetic utility. The scalability of the reaction and the facile derivatization of the products further underscore the robustness and versatility of this protocol. Mechanistic investigations reveal that LnFe⁰ species serve as the initiating catalyst and provide insights into the pathway of this new iron-catalyzed electrophile cross-coupling.