A visible light-induced photoredox-catalyzed assembly-point di/trifunctionalization of diazomethyl radicals†

A visible-light-induced photoredox-catalyzed direct di/trifunctionalization of diazo compounds with electron-rich arenes or terminal alkenes by an assembly-point functionalization strategy of diazomethyl radicals has been developed. This reaction exhibits high regioselectivity and a wide substrate scope and provides an efficient route toward the synthesis of α,α-diaryl- and α,α,α-triaryl-carbonyl compounds, α-arylamino esters, 1,4-dienes and indolizines in a single step. Control experiments and DFT calculations indicate that a free diazomethyl radical intermediate is formed via a photocatalytic single electron transfer process, opening up a novel means to access the diversity of diazo chemistry.