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。
Nickel-Catalyzed Direct Alkynylation of Azoles with Alkynyl Bromides
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