Photocatalytic Germylation via Direct Hydrogen Atom Transfer

Comprehensive Summary An innovative visible‐light‐driven direct hydrogen atom transfer ( d ‐HAT) of Ge–H bond has been developed, wherein the photoexcited 9,10‐phenanthraquinone ( PC HAT 9 ) serves as an efficient photocatalyst for the generation of germanium‐centered radicals from germanium hydrides including Ph 3 GeH, n Bu 3 GeH, and Ph 2 GeH 2 . By employing hypervalent iodine reagents as SOMOphiles, this protocol facilitates streamlined germylation through a mechanism involving germyl radical addition followed by β‐cleavage of a carboxyl radical to yield a diverse array of ethynyl‐, vinyl‐, nitrile‐, and phenyl‐functionalized germanes. The methodological leap signifies a noteworthy departure from the previous photocatalytic indirect hydrogen atom transfer ( i ‐HAT) relying on combined usage of PC SET with abstractors, which not only advances the methodology for creating germanium radicals in a photocatalytic fashion but also provides access to structurally novel and pharmaceutically promising organogermanium compounds that are difficult to synthesize by routine methods.