Reductive dearomative arylcarboxylation of indoles with CO 2 via visible-light photoredox catalysis

Public Time: 2020-06-29 00:00:00
Journal: Nature Communications
doi: 10.1038/s41467-020-17085-9
Author: Wen-Jun Zhou;Zhe-Hao Wang;Li-Li Liao;Yuan-Xu Jiang;Ke-Gong Cao;Tao Ju;Yiwen Li;Guang-Mei Cao;Da-Gang Yu
Summary: Catalytic reductive coupling of two electrophiles and one unsaturated bond represents an economic and efficient way to construct complex skeletons, which is dominated by transition-metal catalysis via two electron transfer. Herein, we report a strategy of visible-light photoredox-catalyzed successive single electron transfer, realizing dearomative arylcarboxylation of indoles with CO2. This strategy avoids common side reactions in transition-metal catalysis, including ipso-carboxylation of aryl halides and β-hydride elimination. This visible-light photoredox catalysis shows high chemoselectivity, low loading of photocatalyst, mild reaction conditions (room temperature, 1 atm) and good functional group tolerance, providing great potential for the synthesis of valuable but difficultly accessible indoline-3-carboxylic acids. Mechanistic studies indicate that the benzylic radicals and anions might be generated as the key intermediates, thus providing a direction for reductive couplings with other electrophiles, including D2O and aldehyde.
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