for the preparation of 3-substituted isocoumarins via palladium-catalyzed nucleophilic addition/oxidative annulation of bromoalkynes with benzoic acids has been developed. Remarkably, preliminary mechanistic studies indicated that the transformation might proceed via a stereo- and regioselective nucleophilic addition and C–H functionalization procedure.
In this paper, we describe the silver triflate/p-toluenesulfonic acid co-catalysed synthesis of seventeen isocoumarins and two thieno[2,3-c]pyran-7-ones starting from 2-alkynylbenzoates and 3-alkynylthiophene-2-carboxylates, respectively. The reaction proceeds with absolute regioselectivity under mild reaction conditions and low catalyst loading, to afford the desired products in good to excellent
在本文中,我们描述了三氟甲磺酸银/对甲苯磺酸共催化合成17个异香豆素和两个由2-炔基苯甲酸酯和3-炔基噻吩-2-羧酸酯组成的噻吩并[2,3 - c ]吡喃-7-,分别。反应在温和的反应条件下和低的催化剂载量下以绝对的区域选择性进行,以良好至极好的收率提供所需的产物。提出了一种可能的反应机理,并得到了同位素交换试验,1 H NMR研究和特别实验的支持。
p-Toluenesulfonic acid-promoted selective functionalization of unsymmetrical arylalkynes: a regioselective access to various arylketones and heterocycles
Regioselective hydration of a wide range of internalalkynes has been afforded in high to good yields by using PTSA in EtOH. The scope of the reaction of alkynes has been delineated. Arylaliphatic alkynes and diarylalkynes were regioselectively hydrated in good to excellent yields and short reaction times when the reaction was achieved under microwave irradiation. Moreover, diarylalkynes, arylenynes
Ru(<scp>ii</scp>)-Catalyzed C–H bond activation/annulation of <i>N</i>-iminopyridinium ylides with sulfoxonium ylides
作者:Xiang Li、Danlu Li、Xiaofei Zhang
DOI:10.1039/d1ob02427b
日期:——
A Ru(II)-catalyzed C–H bond activation/annulation of N-iminopyridinium ylides with sulfoxoniumylides has been developed for the synthesis of diverse functionalized isocoumarin derivatives. This method features broad substrate scope, high functional group tolerance, simple operation and silver salt-free conditions. Furthermore, the synthetic utility of this method is demonstrated by the alkenylation
已经开发了一种 Ru( II ) 催化的N-亚氨基吡啶叶立德与锍叶立德的 C-H 键活化/环化,用于合成各种官能化的异香豆素衍生物。该方法具有底物范围广、官能团耐受性高、操作简单、无银盐条件等特点。此外,该方法的合成效用通过产物的烯基化和生物活性 thunberginol A 的有效合成得到证明。
Synthesis of Isocoumarin via PTSA-Catalyzed Annulation of Diarylalkynes
作者:Olivier Provot、Mouâd Alami、Gaëlle Le Bras、Abdallah Hamze、Samir Messaoudi、Pierre-Benoît Le Calvez、Jean-Daniel Brion
DOI:10.1055/s-2008-1072575
日期:2008.5
p-Toluenesulfonic acid (PTSA) in ethanol was used as a mild acid catalyst for the annulation of various functionalized diarylalkynes under microwave irradiation. This metal-free process allowed the synthesis of a range of 3-aryl-substituted isocoumarins in good yields.