Alkyl‐GeMe3: Neutral Metalloid Radical Precursors upon Visible‐Light Photocatalysis

Abstract Single‐electron transfer (SET) oxidation of ionic hypervalent complexes, in particular alkyltrifluoroborates (Alkyl‐BF 3 − ) and alkylbis(catecholato)silicates (Alkyl‐Si(cat) 2 − ), have contributed substantially to alkyl radical generation compared to alkali or alkaline earth organometallics because of their excellent activity–stability balance. Herein, another proposal is reported by using neutral metalloid compounds, Alkyl‐GeMe 3 , as radical precursors. Alkyl‐GeMe 3 shows comparable activity to that of Alkyl‐BF 3 − and Alkyl‐Si(cat) 2 − in radical addition reactions. Moreover, Alkyl‐GeMe 3 is the first successful group 14 tetraalkyl nucleophile in nickel‐catalyzed cross‐coupling. Meanwhile, the neutral nature of these organogermanes offset the limitation of ionic precursors in purification and derivatization. A preliminary mechanism study suggests that an alkyl radical is generated from a tetraalkylgermane radical cation with the assistance of a nucleophile, which may also result in the development of more non‐ionic alkyl radical precursors with a metalloid center.