The direct C−H alkynylation of azoles with terminal alkynes proceeds efficiently under a nickel/O2 catalytic system. On the other hand, a copper/air catalyst enables the coupling of polyfluoroarenes with terminal alkynes. These catalyses provide new accesses to arylacetylenes through the formal direct Sonogashira coupling.
在镍/ O 2催化体系下,唑类与末端炔烃的直接CH炔基化反应有效进行。另一方面,铜/空气催化剂能够使多氟芳烃与末端炔烃偶联。这些催化剂通过正式的直接Sonogashira偶联为芳基乙炔提供了新的途径。
Room-Temperature Direct Alkynylation of Arenes with Copper Acetylides
作者:Cédric Theunissen、Gwilherm Evano
DOI:10.1021/ol502030y
日期:2014.9.5
C–H bond in azoles and polyhalogenated arenes can be smoothly activated by copper acetylides to give the corresponding alkynylated (hetero)arenes by simple reaction at room temperature in the presence of phenanthroline and lithium tert-butoxide under an oxygen atmosphere. These stable, unreactive, and readily available polymers act as especially efficient and practical reagents for the introduction
The direct C−H alkynylation of azoles with alkynyl bromides proceeds efficiently in the presence of a nickel-based catalyst system. The reaction enables the introduction of various alkynyl groups bearing aryl, alkenyl, alkyl, and silyl substituents to the azole cores. In some cases, addition of a catalytic amount of CuI is observed to accelerate the direct coupling dramatically.
Convenient synthesis of 2-alkynylbenzazoles through Sonogashira cross-coupling reaction between thioethers and terminal alkynes
作者:Anca Paun、Mihaela Matache、Florina Enache、Ioana Nicolau、Codruta C. Paraschivescu、Petre Ionita、Irina Zarafu、Vasile I. Parvulescu、Gérald Guillaumet
DOI:10.1016/j.tetlet.2015.08.001
日期:2015.9
We describe herein the synthesis of 2-alkynylbenzoxazole and 2-alkynylbenzothiazole derivatives through the Sonogashira cross-coupling reaction of the corresponding thioethers and terminal alkynes under aerobic conditions, using CuI and Pd(dppf)Cl2 as catalysts. The synthetic methodology allows the convenient cross-coupling of heteroaromatic substrates with a wide variety of aromatic and aliphatic
Dehydrogenative and decarboxylative C–H alkynylation of heteroarenes catalyzed by Pd(II)–carbene complex
作者:Thupakula Parsharamulu、Police Vishnuvardhan Reddy、Pravin R. Likhar、Mannepalli Lakshmi Kantam
DOI:10.1016/j.tet.2015.02.020
日期:2015.4
The direct alkynylation of heteroarenes was accomplished with easily prepared Pd(II) carbene complex (Pd Cat.) by two complementary strategies. Pd Cat. catalysed cross-dehydrogenative coupling of terminal alkynes with heteroarenes was achieved in the first method and decarboxylative coupling of aryl propiolic acids with heteroarenes was investigated in the second method. Both the methodologies tolerate a broad variety of heteroarenes that include benzoxazoles, benzothiazoles, imidazole and benzimidazoles. (C) 2015 Elsevier Ltd. All rights reserved.