Visible-Light-Mediated Cascade Arylcarboxylation/Cyclization of <i>N</i>-Aryl/Benzoyl Acrylamide with CO<sub>2</sub>
Tao Zhang, Ziren Chen, Fei Xue, Xinxin Ren, Bin Wang, Weiwei Jin, Yu Xia, Shaofeng Wu, Azhar Iqbal, Yonghong Zhang, Chenjiang Liu
Abstract
A visible-light-mediated radical cascade arylcarboxylation/cyclization of N -alkyl- N -methacryloylbenzamides and N -alkyl- N -arylmethacrylamides with carbon dioxide (CO 2 ) was established. The reactions employed economical CO 2 as the carboxyl source, cesium carbonate as the base, triphenylsilane as the additive, and fac -Ir(ppy) 3 as the photocatalyst. Novel 1,3-dioxo-1,2,3,4-tetrahydroisoquinolin-4-ylacetic acid derivatives and oxindole-3-acetic acid derivatives were obtained in moderate to good yields. This methodology shows a wide substrate scope, simple operation, excellent functional group compatibility, mild conditions, gram scale synthesis, and straightforward product derivatization. Detailed mechanistic insights reveal that CO 2 •– generated in situ was invovled as key a key active intermediate under conditions free of external hydrogen atom transfer (HAT) and reducing agents.