Visible‐Light‐Induced C2 Alkylation of Heterocyclic N‐Oxides with N‐Hydroxyphthalimide Esters under Metal‐Free Conditions
Pi‐Tao Qin, Jing Sun, Fei Wang, Jing‐Yun Wang, He Wang, Mingdong Zhou
Abstract
Abstract A visible‐light‐induced site selective C−H alkylation of heterocyclic N‐oxides with N‐hydroxyphthalimide esters was developed using Eosin Y as the photocatalyst in the presence of Cs 2 CO 3 under redox‐neutral and mild conditions. Using N‐hydroxyphthalimide esters as the radical precursors, quinoline and pyridine N‐oxides were readily coupled with a wide range of primary, secondary, and tertiary radicals to afford the desired alkylated heterocyclic N‐oxides in moderated to excellent yields. Importantly, this reaction protocol also successfully demonstrated its applications for the construction of glycosyl or bioactive natural dehydroabietic acid containing heterocyclic N‐oxides, as well as the pharmaceutical and agrochemical active alkylated quinine‐based functional molecules (potential antimalarial drug). magnified image