Quinoline Ligands Improve the Classic Direct C−H Functionalisation/Intramolecular Cyclisation of Diaryl Ethers to Dibenzofurans
作者:Katrina Mackey、David J. Jones、Leticia M. Pardo、Gerard P. McGlacken
DOI:10.1002/ejoc.202001416
日期:2021.1.22
Intramolecular arylation through direct C−H functionalisation is a convenient method for the formation of dibenzofurans. In the Pd‐mediated process, the use of quinoline ligands alleviates a number of the existing issues with the use of phosphineligands.
dibenzoxaborins to dibenzofurans by deborylative ring contraction was achieved under mild conditions using a copper catalyst. The method showed a broad substrate scope enabling the preparation of various dibenzofurans, including those bearing a functional group. The ready availability of various dibenzoxaborins enhances the utility of this method, as demonstrated by the regiodivergent synthesis of dibenzofurans
Nickel-catalyzed intramolecular C–H arylation using aryl pivalates as electrophiles
作者:Jiayi Wang、Devin M. Ferguson、Dipannita Kalyani
DOI:10.1016/j.tet.2013.04.096
日期:2013.7
This paper describes a method for nickel catalyzed intramolecular C-H arylation using aryl pivalates as electrophiles. The transformation is efficient for the synthesis of diverse electronically and sterically differentiated dibenzofurans. Additionally, the method could be expanded toward the synthesis of carbazoles. Preliminary mechanistic studies of the transformation are also described. (C) 2013 Elsevier Ltd. All rights reserved.
Synthesis of Dibenzofurans via Palladium-Catalyzed Phenol-Directed C–H Activation/C–O Cyclization
作者:Bin Xiao、Tian-Jun Gong、Zhao-Jing Liu、Jing-Hui Liu、Dong-Fen Luo、Jun Xu、Lei Liu
DOI:10.1021/ja203335u
日期:2011.6.22
A practical, Pd(0)/Pd(II)-catalyzed reaction was developed for phenol-directed C-H activation/C-O cyclization using air as an oxidant. The turnover-limiting step of the process was found to be C-O reductive elimination instead of C-H activation. This reaction can tolerate a variety of functional groups and is complementary to the previous methods for the synthesis of substituted dibenzofurans.