Assembly of 4H-chromenes, imidazobenzothiazines and quinazolines via copper-catalyzed domino reactions using 2-halobenzyl tosylates as substrates
摘要:
The use of 2-halobenzyl tosylates as substrates in copper-catalyzed domino intermolecular substitution/intramolecular arylation processes for the efficient and selective preparation of heterocycles is reported for the first time. Reaction of 2-halobenzyl tosylates with beta-ketoesters delivers 4H-chromenes with yields ranging between 59 and 89%. Imidazobenzothiazines are formed with yields up to 82% upon reaction of 2-halobenzyl tosylates with 2-mercaptoimidazoles. When 2-halobenzyl tosylates are reacted with benzamidines the corresponding quinazolines are obtained. (C) 2014 Elsevier Ltd. All rights reserved.
Accessing Polysubstituted Quinazolines via Nickel Catalyzed Acceptorless Dehydrogenative Coupling
作者:Seuli Parua、Rina Sikari、Suman Sinha、Gargi Chakraborty、Rakesh Mondal、Nanda D. Paul
DOI:10.1021/acs.joc.8b01479
日期:2018.9.21
easy to prepare nickel catalysts, containing tetraaza macrocyclic ligands (tetramethyltetraaza[14]annulene (MeTAA) or 6,15-dimethyl-8,17-diphenyltetraaza[14]annulene (MePhTAA)) are reported. A wide variety of substituted quinazolines were synthesized in moderate to high yields starting from cheap and easily available starting precursors. A few control reactions were performed to understand the mechanism
Direct synthesis of N-heterocycles via the acceptorless dehydrogenative coupling is very challenging and scarcely reported under 3d transition-metal catalysis. Here, we have developed an efficient Mn(I)-catalyzed sustainable synthesis of various quinoxalines from 1,2-diaminobenzenes and 1,2-diols via the acceptorless dehydrogenative coupling reaction. Further, this strategy was successfully applied
Efficient synthesis of quinazolines by the iron-catalyzed acceptorless dehydrogenative coupling of (2-aminophenyl)methanols and benzamides
作者:Shi-Qi Zhang、Yao Cui、Bin Guo、David J. Young、Ze Xu、Hong-Xi Li
DOI:10.1016/j.tet.2020.131825
日期:2021.1
The acceptorless dehydrogenation coupling (ADC) of (2-aminophenyl)methanols with benzamides was achieved with catalytic FeCl2·4H2O in an efficient synthesis of quinazolines. This simple catalytic system is atom-economical, environmentally benign and suited to a variety of substrates.