Metal-and oxidant-free photocatalytic C-H alkylation of coumarins is developed in the presence of triphenylphosphine and sodium iodide under blue LEDs irradiation by using the easily available alkyl N-hydroxyphthalimide esters as the alkylation reagents. The metal-and oxidant-free decarboxylative C-H coupling protocol provides various 3-alkylated coumarins, as well as quinoxalinones, in satisfactory yields with excellent C-3 regioselectivity.(c) 2022 Elsevier Ltd. All rights reserved.
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