Facial Syntheses of Bromobenzothiazines via Catalyst-Free Tandem C–H Amination/Bromination in Water
摘要:
A transition-metal-free and environmentally friendly synthesis method for bromobenzothiazines through tandem C-H amination/bromination was reported. This reaction contains both intramolecular C-H amination and site-selective electrophilic bromination of arenes with NaBr as the bromo source, PhI(OAc)(2) or K2S2O8 as the oxidant, and H2O as the only solvent.
Investigation of the Mechanism of C(sp<sup>3</sup>)−H Bond Cleavage in Pd(0)-Catalyzed Intramolecular Alkane Arylation Adjacent to Amides and Sulfonamides
作者:Sophie Rousseaux、Serge I. Gorelsky、Benjamin K. W. Chung、Keith Fagnou
DOI:10.1021/ja103081n
日期:2010.8.11
reactivity of C(sp(3))-H bonds adjacent to a nitrogen atom can be tuned to allow intramolecular alkane arylation under Pd(0) catalysis. Diminishing the Lewis basicity of the nitrogen lone pair is crucial for this catalytic activity. A range of N-methylamides and sulfonamides react exclusively at primary C(sp(3))-H bonds to afford the products of alkane arylation in good yields. The isolation of a Pd(II) reaction
to structurally diverse synthesis of benzosultams from aryl sulfonamides through an electrochemical cyclization. Upon variation of the ortho substituent on aryl sulfonamides, five-, six-, and seven-membered benzosultams were efficiently assembled in an atom- and resource-economic manner. The generality of the process is demonstrated by the formation of five- to seven-membered cyclic products from 42
Herein, we report a metal-free radical tandem C–H amination and bromination reaction with dibromohydantoin (DBH) as both the amination and brominationreagents and water as the main solvent. The reaction involves in intramolecular C–H amination and electrophilicbromination using cheap commercially available DBH. The products represent heterocyclic building blocks, readily modifiable by classical cross-coupling
Aryl radical-induced desulfonylative<i>ipso</i>-substitution of diaryliodonium salts: an efficient route to sterically hindered biarylamines
作者:Huangguan Chen、Limin Wang、Jianwei Han
DOI:10.1039/d0cc01766c
日期:——
By using vicinal aryl sulfonamide substituted diaryliodonium salts, a cascade of desulfonylation/aryl migration was promoted by triethylamine in the synthesis of sterically hindered biarylamines, which operated via a radical-induced reaction pathway. The products were readily converted into a variety of important synthons. Furthermore, coupling reactions of N-methyl biarylamine and 1,6-dibromopyrene
The direct arylation of N‐substituted o‐bromobenzanilides and benzenesulfonamides via CH bond functionalization has been developed using very low catalyst loadings. This novel cost‐effective and more sustainable method relies on a PCN‐type palladium pincer complex as a highly active palladium source, providing a general and efficientaccess to phenanthridinones, biaryl sultams and related heterocyclic