1629167-70-9Relevant academic research and scientific papers
Palladium-catalyzed highly regioselective 2-alkynylation of 2,x-dihalopyridines Dedicated to Academician Xikui Jiang on the occasion of his 90th birthday and Professor Zhenchu Chen on the occasion of his 80th birthday
Zhang, Bin,Chen, Rener,Jiang, Huajiang,Zhou, Qizhong,Qiu, Fangli,Han, Deman,Li, Rongrong,Tang, Wenyuan,Zhong, Aiguo,Zhang, Jie,Yu, Xiaochun
, p. 2813 - 2817 (2016)
2,4-Dibromopyridines reacted with arylacetylenes, catalyzed by Pd(CF3COO)2/CuI/PPh3 in the presence of i-Pr2NH in CH3CN at reflux for 24 h, to afford 2-alkynylpyridines in good to high yields, while 2,3- and 2,5-dihalopyridines reacted with arylacetylenes, catalyzed by Pd(OAc)2/CuI/PPh3 in the presence of i-Pr2NH in CH3CN at reflux for 24 h, to afford 2-alkynylpyridines in good to high yields.
Transition-metal-free BF3-mediated oxidative and non-oxidative cross-coupling of pyridines
Chen, Quan,Leon, Thierry,Knochel, Paul
supporting information, p. 8746 - 8750 (2014/08/18)
We report a BF3-mediated direct alkynylation of pyridines at C(2) by using a variety of alkynyllithium reagents (oxidative cross-coupling). Moreover, we have developed a novel transition-metal-free cross-coupling method between alkylmagnesium reagents and 4-substituted pyridines, such as isonicotinonitrile and 4-chloropyridine, by employing BF3· OEt2 as a promoter. The combination of these methods enabled us to efficiently prepare a range of di-, tri-, and tetrasubstituted pyridines. Oxidative or non-oxidative - That is the question! Pyridines bearing a substituent at position 4 readily undergo a BF3-mediated oxidative coupling at position 2 with a wide range of alkynyllithium compounds. In contrast, 4-cyano- or 4-chloropyridines undergo a novel BF3-mediated cross-coupling at position 4 with alkylmagnesium reagents. The combination of the two transition-metal-free procedures allows the preparation of a broad range of pyridines.
