Exploration of N-hydroxy benzimidazole catalysts for hydrogen atom transfer reactions

Abstract

N-Hydroxy benzimidazoles (NHBIs) have proved to be efficient hydrogen atom abstractors (HAAs), but their further application in catalysis has been rarely explored since the first report. Herein, we describe their...

Synthetic Methods for Azaheterocyclic Phosphonates and Their Biological Activity: An Update 2004–2024

“…To access the highly functionalized N-hydroxypyrrole derivatives 360, a [3 + 2]-cycloaddition reaction between 197 More recently, Luan's research group accessed these compounds in moderate to good yields by a copper/N-hydroxy benzimidazole derivative (NHBI, 364) cocatalyzed reaction in a mixture of acetonitrile and dioxane. 198 Demir and Tural reported the synthesis of several 5alkoxypyrrole-3-phosphonates 366 in good yields through a Zn(II)-catalyzed addition/heterocyclisation reaction of αcyanomethyl-β-ketophosphonates 365 in anhydrous alcohol (Scheme 72). By using a mixture of solvents such as MeOH/ water (2/1) or CH 3 CN/water (5:1), it was possible to obtain phosphonopyrrolinones 367 in good yields.…”

“…This protocol uses Ru­(bpy) 3 Cl 2 ·6H 2 O as photocatalyst, NaOAc as a base in an O 2 atmosphere to afford the products in moderate yields via a visible-light photoredox-catalyzed oxidation/[3 + 2] cycloaddition/oxidative aromatization cascade under mild conditions (Scheme ). More recently, Luan’s research group accessed these compounds in moderate to good yields by a copper/ N -hydroxy benzimidazole derivative (NHBI, 364 ) cocatalyzed reaction in a mixture of acetonitrile and dioxane …”