Chemoselective N–H or C-2 Arylation of Indole-2-carboxamides: Controllable Synthesis of Indolo[1,2-a]quinoxalin-6-ones and 2,3′-Spirobi[indolin]-2′-ones DOI
Lingkai Kong, Yue Sun, Zhong Zheng

et al.

Organic Letters, Journal Year: 2018, Volume and Issue: 20(17), P. 5251 - 5255

Published: Aug. 20, 2018

Novel methods involving the chemoselective N-H or C-2 arylation for synthesis of indolo[1,2- a]quinoxalin-6-ones and 2,3'-spirobi[indolin]-2'-ones starting from indole-2-carboxamides were developed. When reactions carried out using ZnI2 as catalyst Ag2CO3 oxidant, synthesized in up to 86% yields via intramolecular N-H/C-H coupling, whereas dearomative cyclization realized presence TfOH, resulting indole through C-H functionalization a Fridel-Crafts alkylation reaction give moderate excellent yields.

Language: Английский

HFIP-mediated three-component imidization of electron-rich arenes with in situ formed spiroindolenines for facile construction of 2-arylspiroindolenines DOI

Chunyan Ge,

Liang Wang, Fangzhi Hu

et al.

Organic Chemistry Frontiers, Journal Year: 2022, Volume and Issue: 9(6), P. 1696 - 1702

Published: Jan. 1, 2022

The three-component reaction of o -aminobenzaldehydes with 5-hydroxyindole and electron-rich arenes has been achieved through HFIP-mediated cascade hydride transfer/dearomative cyclization/CDC-type imidization at room temperature under air.

Language: Английский

Citations

16
Metal‐Free Dearomatization: Direct Access to Spiroindol(en)ines in Batch and Continuous‐Flow DOI
Prabhat Ranjan, Gerardo M. Ojeda‐Carralero, Upendra K. Sharma

et al.

Chemistry - A European Journal, Journal Year: 2018, Volume and Issue: 25(10), P. 2442 - 2446

Published: Dec. 3, 2018

Abstract A metal‐free, phosphine‐catalyzed intramolecular “umpolung Michael addition” on alkynes to form spiroindol(en)ines is reported. This nucleophilic catalysis enables the formation of a wide scope five‐ and six‐membered in moderate excellent yields batch as well under continuous‐flow conditions. Triphenylphosphine‐catalyzed activation allows exclusive exo ‐product mild reaction

Language: Английский

Citations

27
Specific Synthesis of 3H-Indole Derivatives via Rh(III)-Catalyzed Cascade Annulation between N-Phenylbenzimidamides and Pyridotriazoles DOI

Hui‐Bei Xu,

Yanying Zhu,

Lin Dong

et al.

The Journal of Organic Chemistry, Journal Year: 2019, Volume and Issue: 84(24), P. 16286 - 16292

Published: Nov. 19, 2019

An efficient synthetic method to construct 3H-indole derivatives has been successfully developed involving rhodium-catalyzed highly selective C–H bond activation of N-phenylbenzimidamides and subsequent couplings with pyridotriazoles. This cascade approach features excellent chemoselectivity unique products containing quaternary carbon center the pyridyl moiety.

Language: Английский

Citations

25
Enantioselective Synthesis of Spiroindolines via Cascade Isomerization/Spirocyclization/Dearomatization Reaction DOI
Zhiqiang Pan,

Yuchang Liu,

Fengchi Hu

et al.

Organic Letters, Journal Year: 2020, Volume and Issue: 22(4), P. 1589 - 1593

Published: Jan. 28, 2020

The spiroindoline skeleton featured with 2,7-diazaspiro[4.4]nonane exists in various structurally intricate and biologically active monoterpene indole alkaloids. A catalytic asymmetric cascade enamine isomerization/spirocyclization/dearomatization succession to construct the was developed, which employed indolyl dihydropyridine as a substrate under catalysis of chiral phosphoric acid. This reaction provided spiroindolines both diastereoselective enantionselective fashions.

Language: Английский

Citations

22
Chemoselective N–H or C-2 Arylation of Indole-2-carboxamides: Controllable Synthesis of Indolo[1,2-a]quinoxalin-6-ones and 2,3′-Spirobi[indolin]-2′-ones DOI
Lingkai Kong, Yue Sun, Zhong Zheng

et al.

Organic Letters, Journal Year: 2018, Volume and Issue: 20(17), P. 5251 - 5255

Published: Aug. 20, 2018

Novel methods involving the chemoselective N-H or C-2 arylation for synthesis of indolo[1,2- a]quinoxalin-6-ones and 2,3'-spirobi[indolin]-2'-ones starting from indole-2-carboxamides were developed. When reactions carried out using ZnI2 as catalyst Ag2CO3 oxidant, synthesized in up to 86% yields via intramolecular N-H/C-H coupling, whereas dearomative cyclization realized presence TfOH, resulting indole through C-H functionalization a Fridel-Crafts alkylation reaction give moderate excellent yields.

Language: Английский

Citations

22