LiBr-Promoted Photoredox Minisci-Type Alkylations of Quinolines with Ethers

A visible-light-mediated photoredox Minisci-type alkylation with ethers as the alkylating reagent is reported. User-friendly LiBr has been found to be the key promoter for this radical coupling. The reaction exhibits broad functional group tolerance for both C2 and C4 couplings/alkylations of quinolines. Mechanistic studies suggest that the bromide additive could not only dramatically enhance the reaction but also alter the reaction mechanism probably over a reductive catalytic cycle.