Photoinduced radical germyloximation of activated alkenes†

Abstract

This study unveils a photoinduced radical germyloximation strategy for the bifunctionalization of activated alkenes under photocatalyst-, metal-, and additive-free conditions. This methodology leverages the homolytic cleavage of the O–NO bond in tert-butyl nitrite under light irradiation to generate a reactive tert-butoxyl radical and a persistent nitric oxide (NO) radical. The tert-butoxyl radical can act as a hydrogen atom transfer (HAT) reagent of a germane hydride to afford germyl radicals that subsequently undergo regioselective addition to activated alkenes, followed by cross-coupling with the NO radical to yield α-germyl oximes. Late-stage germyloximation of pharmaceutically relevant complex molecules underscores the synthetic applicability and downstream derivatization of α-germyl oxime derivatives highlights the practical versatility. Overall, this novel protocol substantially expands the repertoire of tools for constructing structurally distinct 3D aliphatic germanes and holds considerable promise for advancing germanium-based chemical research.