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

One-step construction of substituted indolizino­[1,2-b]­quinolin-9­(11H)-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.