Lewis Acidic Ionic-Liquid-Catalyzed Radical-Cascade Alkylation/Cyclization of -Alkyl--methacryloyl Benzamides with Alkanes via Visible-Light-Induced Ligand-to-Metal Charge Transfer: Access to Alkylated Isoquinoline-1,3(2,4)-diones.

With the flourishing progress of ligand-to-metal charge transfer (LMCT) photocatalysis, various metals were developed as catalysts to activate abundant alkane feedstocks for the synthesis of functionalized organic compounds. However, to the best of our knowledge, most of the LMCT catalysts are difficult to recover and reuse for the next cycles. Herein, we report a reusable Lewis acidic ionic liquid (LAIL)-catalyzed radical-cascade alkylation/cyclization of -alkyl--methacryloyl benzamides with unactivated alkanes for the synthesis of alkylated isoquinoline-1,3-(2,4)-diketones. The protocol features mild reaction conditions, high atom utilization efficiency, scale-up synthesis, simple operation, and recycling of catalysts.