A combination of LiO‐tBu, CsF, and 18‐crown‐6 can be used to carboxylate indole derivatives at the C‐2 position under an ambient CO₂ atmosphere. Substrates bearing an electrophilic substituent (i.e. CN, formyl, benzoyl, phenylsulfonyl, phenylsulfinyl, and chloride) at the C‐3 position are smoothly converted into their corresponding carboxylated products with high functional group compatibility.

中文翻译：

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使用LiO-tBu / CsF / 18-crown-6组合的Brønsted碱直接取代3取代的吲哚的C-2羧基

LiO-的组合吨卜，CsF和18-冠-6可用于羧酸盐的环境CO下在C-2位的吲哚衍生物₂的气氛。在C-3位置带有亲电取代基（例如CN，甲酰基，苯甲酰基，苯磺酰基，苯亚磺酰基和氯化物）的底物可以平滑地转化为具有高官能团相容性的相应羧化产物。