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。
Boron‐Mediated Regioselective Aromatic C−H Functionalization via an Aryl BF
<sub>2</sub>
Complex
作者:Ganesh H. Shinde、Henrik Sundén
DOI:10.1002/chem.202203505
日期:2023.2.16
Regioselectivefunctionalization of 2-aryl-azaarenes N-heteroarenes and aryl aldehydes has been achieved. The reaction proceeds via a BBr3 promoted 5 and 6-membered boracycle that undergoes a ligand exchange promoted by Selectfluor to give a previously scarce aryl BF2 species. The aryl BF2 is a bench stable intermediate that can be used for the deborylative functionalization of the 2-aryl-azaarenes
Ru‐catalyzed direct CH activation/meta‐bromination of arenes bearing pyridyl, pyrimidyl, and pyrazolyl directing groups has been developed. A series of bromo aryl pyridines and pyrimidines have been synthesized, and further coupling reactions have also been demonstrated for a number of representative functionalized arenes. Preliminary mechanistic studies have revealed that this reaction may proceed through