Copper(I) Photocatalytic Three-Component Acylative Germylation of Unactivated Olefins with Aroyl Chlorides and CsGeBr3.

We report a Cu(I) photocatalytic three-component acylative germylation of unactivated olefins using aroyl chlorides and CsGeBr3, which is an inorganic Ge(II) source. The reaction generates alkylgermanium bromides that are converted with MeMgBr into diverse alkyltrimethylgermanes with broad functional group tolerance, including complex molecular substrates. Mechanistic studies reveal that CsGeBr3 not only provides the germanium source but also promotes the generation of catalytically relevant copper species, highlighting the cooperative interaction between Ge(II) and Cu(I).