Regiochemistry and mechanism of oxidation ofN-benzyl-N-alkylhydroxylamines to nitrones
摘要:
The oxidation of various N-(o-, m-, p-substituted benzyl)-N-alkylhydroxylamines and their dideuteriobenzyl (PhCD2) counterparts was carried out using mercury(II) oxide and p-benzoquinone (p-BQ) as oxidants. An overwhelming preference for the formation of conjugated nitrones is observed in the oxidation of N-benzyl-N-isopropylhydroxylamines. Considerable intra- and intermolecular kinetic isotope effects and negative rho values in the Hammet plots point towards a mechanistic pathway that involves electron transfer from nitrogen to the oxidant followed by hydrogen abstraction. The conformation of unstable (E)-nitrones, which readily isomerize to the more stable (Z)-nitrones, is deduced from H-1 NMR data. The E = Z isomerization was found to be a bimolecular process. Copyright (C) 2000 John Wiley & Sons, Ltd.
One-Pot Synthesis of Functionalized Nitrones from Nitro Compounds
作者:Valérie Gautheron-Chapoulaud、Shashi U. Pandya、Pascale Cividino、Géraldine Masson、Sandrine Py、Yannick Vallée
DOI:10.1055/s-2001-16042
日期:——
The zinc-mediated reduction of nitroalkanes and nitroarenes in the presence of aldehydes is an efficient method to synthesize a wide range of nitrones. This method is mild enough to accommodate a variety of functional groups. It is particularly useful when the intermediate hydroxylamines are unstable and/or water-soluble. We used it to prepare several aromatic, aliphatic and highly functionalized sugar-derived nitrones.
synthesis of nitronesfrom bench stable amines has been developed under constant current electrolysis at room temperature, rendering metal and external oxidant-free protocol in an alkaline medium. The electrocatalysis steps of reported strategy involve anodic oxidation of benzyl amines followed by cathodic reduction of nitro-functional group in an undivided cell affording functional nitrones. The robustness
Palladium-Catalyzed Synthesis of Nitrones Via Redox Cross-Coupling of Nitro Compounds and Alcohols
作者:Jian Xing、Hong-Yu Tang、Jing-Lin Chen、Zheng Huang、Jun-Jie Liang、Yao-Sheng Quan、Jian-Gang Mao
DOI:10.1021/acs.joc.4c00512
日期:2024.7.19
methodology for the synthesis of nitrones via palladium-catalyzed redox cross-coupling of nitro compounds and alcohols is established. The protocol is a mild, convenient, ligand-free, and scalable synthesis method that can be compatible with various nitro compounds and alcohols. Nitrone is a significant multifunctional platform synthon which can be synthesized directly and efficiently via this tactic from