Synthesis of 3-arylcoumarins through N-heterocyclic carbene catalyzed condensation and annulation of 2-chloro-2-arylacetaldehydes with salicylaldehydes
作者:Yuansong Jiang、Wanzhi Chen、Weimin Lu
DOI:10.1016/j.tet.2013.03.025
日期:2013.5
The condensation reaction of 2-chloro-2-arylacetaldehyde with salicylaldehyde catalyzed by N-heterocyclic carbene (NHC) leading to 3-arylcoumarin was studied. A number of 3-arylcoumarin derivatives were obtained in good to excellent yields via this umpolung reaction. This reaction is facile and experimentally simple and mild.
arylation and aroylation of coumarins with glyoxals in a metal-free manner is presented. The aryl glyoxal is for the first time recognized to serve as an aryl surrogate in addition to its role as an aroyl transfer reagent via a simple switch in reaction conditions. The approach accommodates a broad substrate scope and high yields of the two types of cross-coupling reactions starting from identical starting
Visible-light-driven copper-catalyzed aerobic oxidative cascade cyclization of <i>N</i>-tosylhydrazones and terminal alkynes: regioselective synthesis of 3-arylcoumarins
first example of sustainable, intuitive, highly regioselective, visible-light-driven copper catalyzed aerobic oxidative cascade cyclization of N-tosylhydrazones with terminal alkynes for the preparation of 3-arylcoumarins at room temperature. This operationally simple methodology has been successfully applied to a wide range of N-tosylhydrazones and alkynes (49 examples), and proceeds well to afford biologically
我们提出了可持续的,直观的,高度区域选择性的,可见光驱动的铜催化的N-甲苯磺酰with与末端炔烃的有氧氧化级联环化反应,以在室温下制备3-芳基香豆素。这种操作简单的方法已成功应用于各种N-甲苯磺酰hydr和炔烃(49个实例),并且进展顺利,可提供具有生物活性的化合物,例如单胺氧化酶B(MAO-B)抑制剂和辣根过氧化物酶(HRP)抑制剂,在温和的条件下具有令人满意的产量。此外,机理研究表明,反应是通过铜进行的(II18 O 2同位素标记实验证明)-超氧或-过氧配合物介导的末端炔烃的氧化环化反应。
Chlorophyll-catalyzed photochemical regioselective coumarin C–H arylation with diazonium salts
作者:Ali Moazzam、Farnaz Jafarpour
DOI:10.1039/d0nj02012e
日期:——
A metal-free, direct C–H arylation of coumarins with aryl diazonium salts at room temperature using chlorophyll as a green photosensitizer is devised.
An ultrasound-assisted one-pot acylation/cyclization reaction between N-acylbenzotriazoles and 2-hydroxybenzaldehydes has been developed for the synthesis of substituted 3-arylcoumarins. Using ultrasound not only allows rapid and clean conversion but also simplifies experimental setup and parallel workup leading to rapid generation of 3-arylcoumarin libraries under mild, solvent-free, and chromatography-free