246247-91-6Relevant articles and documents
Organocatalytic cascade aldimine condensation/[1,6]-hydride transfer/Mannich-type cyclization: Sustainable access to indole-2,3-fused diazocanes
An, Xiao-De,Dong, Pei-Zhen,Liu, Rui-Bin,Qiu, Bin,Wang, Lin-Xuan,Xiao, Jian
supporting information, p. 8181 - 8186 (2021/11/01)
An unprecedented organocatalytic cascade aldimine condensation/[1,6]-hydride transfer/Mannich-type cyclization of indole-2-carbaldehydes with o-aminoanilines was developed to assemble polycyclic indole-2,3-fused diazocanes in one step. This novel methodol
1,2-Disubstituted Benzimidazoles by the Iron Catalyzed Cross-Dehydrogenative Coupling of Isomeric o-Phenylenediamine Substrates
Foss, Frank W.,Palacios, Philip M.,Pierce, Brad S.,Thapa, Pawan,Tran, Tam
, p. 1991 - 2009 (2020/03/13)
Benzimidazoles are common in nature, medicines, and materials. Numerous strategies for preparing 2-arylbenzimidazoles exist. In this work, 1,2-disubstituted benzimidazoles were prepared from various mono- and disubstituted ortho-phenylenediamines (OPD) by iron-catalyzed oxidative coupling. Specifically, O2 and FeCl3·6H2O catalyzed the cross-dehydrogenative coupling and aromatization of diarylmethyl and dialkyl benzimidazole precursors. N,N′-Disubstituted-OPD substrates were significantly more reactive than their N,N-disubstituted isomers, which appears to be relative to their propensity for complexation and charge transfer with Fe3+. The reaction also converted N-monosubstituted OPD substrates to 2-substituted benzimidazoles; however, electron-poor substrates produce 1,2-disubstituted benzimidazoles by intermolecular imino-transfer. Kinetic, reagent, and spectroscopic (UV-vis and EPR) studies suggest a mechanism involving metal-substrate complexation, charge transfer, and aerobic turnover, involving high-valent Fe(IV) intermediates. Overall, comparative strategies for the relatively sustainable and efficient synthesis of 1,2-disubstituted benzimidazoles are demonstrated.
Metal-Free Synthesis of Polycyclic Quinazolinones Enabled by a (NH4)2S2O8-Promoted Intramolecular Oxidative Cyclization
Xie, Lijuan,Lu, Cong,Jing, Dong,Ou, Xinrui,Zheng, Ke
supporting information, p. 3649 - 3653 (2019/06/04)
An efficient metal-free, (NH4)2S2O8 mediated intramolecular oxidative cyclization for the construction of polycyclic heterocycles was disclosed. A series of polycyclic quinazolinone derivatives with good functional group tolerance were obtained in high yields. The natural products tryptanthrin and rutaecarpine, as well as their derivatives, were easily synthesized by this strategy. A preliminary mechanism study suggested the carbon-centered radical was involved in the catalytic cycle.