A Novel Palladium-Catalyzed Synthesis of 1,2-Dihydroquinoxalines and 3,4-Dihydroquinoxalinones
摘要:
[GRAPHICS]Reactions of enamines, derived from 2-nitroanilines and alpha-substituted aldehydes, with carbon monoxide (6 atm) in the presence of a catalytic amount of bis(dibenzylideneacetone)palladium(0) (Pd(dba)(2)) and 1,3-bis(diphenylphosphino)propane (dppp) afford readily separated mixtures of 1,2-dihydroquinoxalines and 3,4-dihydroquinoxalinones. Addition of a catalytic amount of 1,10-phenanthroline to the reaction mixture substantially improved the yield of products.
A facile base-mediated synthesis of N-alkoxy-substituted benzimidazoles
作者:Nurul H. Ansari、Arica L. Jordan、Björn C.G. Söderberg
DOI:10.1016/j.tet.2017.06.063
日期:2017.8
Base mediated cyclization of enamines derived from condensation of 2-nitroanilines with α-branched aldehydes, in the presence of an electrophile, affords N-alkoxy-substituted benzimidazoles with or without an oxygenate side chain in the 2-position.
Synthesis of N-alkoxy-substituted 2H-benzimidazoles
作者:Nurul H. Ansari、Björn C.G. Söderberg
DOI:10.1016/j.tetlet.2017.11.007
日期:2017.12
Treatment of 2-nitro-N-(2-methyl-1-propen-1-yl)benzenamines with potassium tert-butoxide in tert-butanol followed by the addition of an electrophile affords N-alkoxy-2H-benzimidazoles. Electrophiles including methyl iodide, allylic bromides, propargylic bromides, benzyl bromide, and acetyl chloride gave good to excellent yields of product while 1-iodo- and 2-iodo-butane afforded very low yields.
Palladium-catalyzed synthesis of quinoxaline derivatives
作者:Jeffery M. Wallace、Björn C.G. Söderberg、Joaquín Tamariz、Novruz G. Akhmedov、Mathew T. Hurley
DOI:10.1016/j.tet.2008.07.083
日期:2008.10
A palladium-catalyzed reductive N-heteroannulation of enamines derived from 2-nitrobenzenamines forming mixtures of 1,2-dihydroquinoxalines and 3,4-dihydroquinoxalin-2-ones is described. The reactions are performed using bis(dibenzylideneacetone)palladium(0), 1,3-bis(diphenylphosphino)propane, and 1,10-phenanthroline in DMF under 6 atm of carbon monoxide at 70 degrees C. (C) 2008 Elsevier Ltd. All rights reserved.
Enantioselective C2-Allylation of Benzimidazoles Using 1,3-Diene Pronucleophiles
作者:James Levi Knippel、Yuxuan Ye、Stephen L. Buchwald
DOI:10.1021/acs.orglett.1c00306
日期:2021.3.19
for their derivatization are still limited. Previously, several enantioselectiveallylation reactions of benzimidazoles were reported that functionalize the nucleophilic nitrogen atom. Herein we describe a reversal of this inherent selectivity toward N-allylation by using electrophilic N-OPiv benzimidazoles with readily available 1,3-dienes as nucleophile precursors. This CuH-catalyzed approach utilizes
A Novel Palladium-Catalyzed Synthesis of 1,2-Dihydroquinoxalines and 3,4-Dihydroquinoxalinones
作者:Björn C. G. Söderberg、Jeffery M. Wallace、Joaquín Tamariz
DOI:10.1021/ol025640g
日期:2002.4.1
[GRAPHICS]Reactions of enamines, derived from 2-nitroanilines and alpha-substituted aldehydes, with carbon monoxide (6 atm) in the presence of a catalytic amount of bis(dibenzylideneacetone)palladium(0) (Pd(dba)(2)) and 1,3-bis(diphenylphosphino)propane (dppp) afford readily separated mixtures of 1,2-dihydroquinoxalines and 3,4-dihydroquinoxalinones. Addition of a catalytic amount of 1,10-phenanthroline to the reaction mixture substantially improved the yield of products.