title: Synthesis of 3-carboxylated indoles through a tandem process involving cyclization of 2-ethynylanilines followed by CO2 fixation in the absence of transition metal catalysts.
abstract: In this study, a facile synthesis of 3-carboxylated indoles involving a tandem-type cyclization of 2-ethynylanilines and subsequent CO2 fixation at the 3-position of the indole ring is realized. The reaction proceeds efficiently at 65 °C under 10 atm of CO2, giving rise to variously substituted 3-carboxylated indoles, generally in high yields. An inorganic base, such as K2CO3, is the only reagent required, and the addition of transition metal catalysts is not necessary. The method provides a novel, simple, and promising strategy for CO2 fixation in the research field of heterocyclic chemistry.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Tohoku University , 6-3, Aoba, Aramaki, Aoba-ku, Sendai 980-8578, Japan.
authors.forename: Kiyofumi
authors.initials: K
authors.lastname: Inamoto
authors.forename: Narumi
authors.initials: N
authors.lastname: Asano
authors.forename: Yuka
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Misato
authors.initials: M
authors.lastname: Yonemoto
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Kondo
mesh_terms: D000814:Aniline Compounds / Q000737:chemistry*; D002245:Carbon Dioxide / Q000737:chemistry*; D002264:Carboxylic Acids / Q000138:chemical synthesis* / Q000737:chemistry; D002384:Catalysis; D020650:Combinatorial Chemistry Techniques; D003500:Cyclization; D007211:Indoles / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure
chemical_list: D000814:Aniline Compounds; D002264:Carboxylic Acids; D007211:Indoles; D002245:Carbon Dioxide