Visible-light-Enabled O-Selective Radical Etherification of 1,2-Dicarbonyl Compounds for the Synthesis of Sterically Congested Ethers

A visible-light-promoted, triphenylphosphine-mediated strategy enables the direct O-selective etherification of 1,2-diketones using NHPI esters as alkyl radical precursors.The method provides an efficient route to sterically congested ethers under mild conditions and accommodates a range of tertiary alkyl radicals and 1,2-diketone derivatives.Mechanistic experiments and DFT calculations support a radical-mediated pathway.Integration into a photochemical continuous-flow platform improves reaction efficiency and scalability while providing greater operational control.