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I + /TBHP Catalysis For Tandem Oxidative Cyclization To Indolo[2,3‐ b ]quinolines
Author(s) -
Uyanik Muhammet,
Tanaka Hiroki,
Ishihara Kazuaki
Publication year - 2021
Publication title -
asian journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.846
H-Index - 44
eISSN - 2193-5815
pISSN - 2193-5807
DOI - 10.1002/ajoc.202000570
Subject(s) - chemistry , indole test , aniline , catalysis , sulfonate , tandem , aromatization , oxidative phosphorylation , salt (chemistry) , organic chemistry , iodide , ionic bonding , medicinal chemistry , combinatorial chemistry , ion , sodium , composite material , biochemistry , materials science
We report a chemoselective tandem oxidative cyclization/aromatization of indole derivatives tethered to aniline sulfonamides using catalytic amount of tetrabutylammonium iodide in the presence of tert ‐butyl hydroperoxide (TBHP) as an oxidant under nearly neutral conditions at room temperature. The corresponding indolo[2,3‐ b ]quinolines were obtained as sulfonate salts, which could be easily isolated in analytically pure form via only a simple filtration of the crude reaction mixture. The natural product quinindoline could be easily obtained after basic work‐up of the sulfonate salt. Control experiments revealed that both ionic and radical active species could be generated in situ under mild conditions for the corresponding oxidative transformations to proceed in a chemoselective manner.