Amine‐Free, Directing‐Group‐Free and Redox‐Neutral α‐Alkylation of Saturated Cyclic Ketones

Amine catalysis is powerful for C−H bond functionalization of carbonyl compounds in chemical synthesis. For an α-C−H bond activation of ketone, directing groups are also required to guide the reaction selectivity. Represented herein is the first α-alkylation of cyclic ketones in the absence of amine catalyst and directing group.1H NMR, XPS, EPR studies and DFT calculation indicate that an α-carbon radical intermediate is formed through direct and selective activation of inert α-C–H bond of ketones chelating on the surface of colloidal quantum dots (QDs) catalyst, which is essential to weaken the C–H bond. As examplified, the activation platform using CdSe QDs as sole photocatalyst executes α-C−H alkylation of cyclic ketones with alkenes under visible light irradiation. Without amine catalyst and directing group, the high step- and atom-economy transformation under redox-neutral condition opens a new way for α-C−H functionalization of ketone in carbonyl chemistry.