Visible-Light-Induced Radical Cascade Cyclization: Synthesis of the ABCD Ring Cores of Camptothecins

A new strategy for constructing indolizino­[1,2-<i>b</i>]­quinolin-9­(11<i>H</i>)-ones (ring cores of camptothecins) from readily available isocyanoarenes and <i>N</i>-(alkyl-2-yn-1-yl)­pyridin-2­(1<i>H</i>)-ones has been developed through a visible-light-induced radical cascade cyclization process. The reaction proceeds under mild conditions with fair to excellent yields. The easy introduction of substituents for both reactants and the broad functional group tolerance of the reaction make it a straightforward route to the cores of the marketed camptothecins and their derivatives

Visible-Light-Induced Radical Cascade Cyclization: Synthesis of the ABCD Ring Cores of Camptothecins

A new strategy for constructing indolizino­[1,2-<i>b</i>]­quinolin-9­(11<i>H</i>)-ones (ring cores of camptothecins) from readily available isocyanoarenes and <i>N</i>-(alkyl-2-yn-1-yl)­pyridin-2­(1<i>H</i>)-ones has been developed through a visible-light-induced radical cascade cyclization process. The reaction proceeds under mild conditions with fair to excellent yields. The easy introduction of substituents for both reactants and the broad functional group tolerance of the reaction make it a straightforward route to the cores of the marketed camptothecins and their derivatives

Visible-Light-Induced Photocatalytic Aerobic Oxidation/Povarov Cyclization Reaction: Synthesis of Substituted Quinoline-Fused Lactones

A one-step construction of quinoline-fused lactones was achieved by visible-light-induced photocatalytic aerobic oxidation/Povarov cyclization reaction. This method provides a new access to the synthesis of important fused heterocycles under mild reaction conditions

Combining Visible-Light-Photoredox and Lewis Acid Catalysis for the Synthesis of Indolizino­[1,2‑<i>b</i>]­quinolin-9(11<i>H</i>)‑ones and Irinotecan Precursor

One-step construction of substituted indolizino­[1,2-<i>b</i>]­quinolin-9­(11<i>H</i>)-ones was achieved by combining visible-light-photoredox and Lewis acid catalysis for an intramolecular Povarov cycloaddition reaction under mild conditions. In this catalytic process, the visible-light-promoted dehydrogenation protocol of tetrahydro­quinolines constitutes the key procedure. Moreover, this method can be applied to the formal synthesis of the precursor of irinotecan, which exhibited good anticancer activities