Direct C‐2 Carboxylation of 3‐Substituted Indoles Using a Combined Brønsted Base Consisting of LiO‐<i>t</i>Bu/CsF/18‐crown‐6
Masanori Shigeno, Itsuki Tohara, Kanako Nozawa‐Kumada, Yoshinori Kondo
Abstract
Herein, we report that a combination of LiO‐ t Bu, CsF, and 18‐crown‐6 can be used to carry out the carboxylation of indole derivatives at the C‐2 position under an ambient CO 2 atmosphere. Substrates bearing an electrophilic substituent (i.e., cyano, formyl, benzoyl, phenylsulfonyl, phenylsulfinyl, and chloride) at the C‐3 position are smoothly converted into their corresponding carboxylated products with high functional group compatibility.
Topics & Concepts
ChemistryCarboxylationSubstituentBenzoyl chlorideElectrophileMedicinal chemistryStereochemistryOrganic chemistryCatalysisCarbon dioxide utilization in catalysisFluorine in Organic ChemistryCatalytic C–H Functionalization Methods