Direct, Site‐Selective and Redox‐Neutral α‐C−H Bond Functionalization of Tetrahydrofurans via Quantum Dots Photocatalysis

As one of the most ubiquitous bulk reagents available, the intrinsic chemical inertness of tetrahydrofuran (THF) makes direct and site‐selective C(sp3)−H bond activation difficult, especially under redox neutral condition. Here, we demonstrate that semiconductor quantum dots (QDs) can activate α‐C−H bond of THF via forming QDs/THF conjugates. Under visible light irradiation, the resultant alkoxyalkyl radical directly engages in radical cross‐coupling with α‐amino radical from amino C−H bonds or radical addition with alkene or phenylacetylene, respectively. In contrast to stoichiometric oxidant or hydrogen atom transfer reagents required in previous studies, the scalable benchtop approach can execute α‐C−H bond activation of THF only by a QD photocatalyst under redox‐neutral condition, thus providing a broad of value added chemicals starting from bulk THFs reagent. As one of the most ubiquitous bulk reagents available, THF is activated by visible light irradiation of quantum dots in a direct, site‐selective and redox‐neutral manner. The resultant α‐oxyalkyl radicals, generated from α‐C−H of THF on the surface of QD, enable either coupling with the α‐amino radical of amines, or addition to chromones and terminal alkynes.