Cu-Mediated Direct Aryl CH Halogenation: a Strategy to Control Mono- and Di-Selectivity
作者:Zhi-Jun Du、Lian-Xun Gao、Ying-Jie Lin、Fu-She Han
DOI:10.1002/cctc.201300734
日期:2014.1
A protocol for the copper‐mediated directarylCHhalogenation is presented. Highly selective mono‐ and di‐halogenations are achieved by using acyl hypohalites, generated in situ from the readily available carboxylic acid and N‐halosuccinimides (NXS; X=Br and Cl) as powerful halogenating reagents. The correct choice of carboxylic acid additives and solvents is essential for both high yield and selectivity
提出了铜介导的直接芳基CH卤化的方案。通过使用酰基次卤酸盐来实现高度选择性的单卤化和二卤化,酰基次卤酸盐是由现成的羧酸和N-卤代琥珀酰亚胺(NXS; X = Br和Cl)原位生成的,作为强力卤化试剂。正确选择羧酸添加剂和溶剂对于高收率和选择性都至关重要。因此,使用廉价的铜催化剂和从容易负担得起且易于处理的羧酸和NXS(X = Br和Cl)原位生成酰基次卤酸盐卤化试剂的新策略为实际应用提供了优势。
Salen-based hypercrosslinked polymer-supported Pd as an efficient and recyclable catalyst for C–H halogenation
In this work, we report the first use of a salen-based hypercrosslinked polymer-supportedPdcatalyst to carry out C-H halogenation. This catalyst can effectively catalyze C-H bromination and chlorination even better than its homogeneous counterpart Pd(OAc)2. It also showed excellent reusability without loss of catalytic activity for ten cycles. A broad substrate scope was explored and moderate to
The first example of a Cu-promoted ortho -chlorination of aryl C–H bonds by using TMSCCl 3 as chlorinating agent is reported. This reaction features a high selectivity toward monochlorination over dichlorination, compatibility with a variety of functional groups, and gram-scale synthesis.
报道了使用 TMSCCl 3 作为氯化剂对芳基 C-H 键进行 Cu 促进邻位氯化的第一个例子。该反应的特点是单氯化比二氯化具有高选择性、与多种官能团的相容性以及克级合成。
Palladium-Catalyzed Chelation-Assisted C–H Bond Halogenation: Selective Chlorination of 2-Arylpyridines with Acid Chlorides
Abstract Palladium-catalyzedchelation-assistedC–H bond halogenation of arenes using acid chlorides as chlorinating agents is reported. This method provides a monoselective, straightforward, and clean route for the construction of aryl chlorides as privileged motifs in organic transformations. Palladium-catalyzedchelation-assistedC–H bond halogenation of arenes using acid chlorides as chlorinating
copper-catalyzed C-H halogenation of 2-aryl-pyridinescontaining a variety of electron-withdrawing and electron-donatingsubstituents was described. It is worth noting that cheap and easy-to-handlelithium halides were utilized as the halogen sources.