Copper-catalyzed direct synthesis of furans and thiophenes via decarboxylative coupling of alkynyl carboxylic acids with H2O or Na2S
摘要:
2,5-Diaryl-substituted furans were synthesized from the copper-catalyzed decarboxylative coupling of aryl-substituted aryl propiolic acids in the presence of H2O. The homocoupling of alkynyl carboxylic acids provided 1,4-diaryldiynes, which then reacted with H2O to give the desired furans through cyclization. Addition of the copper catalyst was critical, and the addition of a ligand increased the yield of products in both the homocoupling and cyclization reactions. In addition, thiophenes could be obtained when the reaction was conducted in the presence of Na2S. (C) 2015 Elsevier Ltd. All rights reserved.
5-Di(hetero)arylfurans are readilyaccessible in a pseudo five-component reactionvia a Sonogashira-Glaser coupling sequence followed by a superbase-mediated (KOH/DMSO) cyclization in a consecutive one-pot fashion. Besides the straightforward synthesis of natural products and biologically active molecules all representatives are particularly interesting due to their bright blue luminescence with remarkably
Palladium‐Catalyzed Cross‐Coupling of Furfuryl Alcohols with Arylboronic Acids
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Aromatization‐Driven Carbon−Carbon Bond Cleavage to Synthesize 5‐Arylfurfuryl Alcohols and 2,5‐Diaryl Furans
作者:Guanghao Huang、Biaolin Yin
DOI:10.1002/adsc.201900799
日期:2019.12.17
Herein we report a protocol for novel palladium‐catalyzed cross‐coupling reactions of sustainably produced primary furfuryl alcohols with arylboronicacids to deliver 5‐arylfurfuryl alcohols and 2,5‐diaryl furans. Hammett plot analysis suggested that the reaction mechanism involved aromatization‐driven cleavage of the carbon−carbon bond of a furan oxonium ion intermediate. This protocol provides a
Sequential Synthesis of Furans from Alkynes: Successive Ruthenium(II)- and Copper(II)-Catalyzed Processes
作者:Min Zhang、Huan-Feng Jiang、Helfried Neumann、Matthias Beller、Pierre H. Dixneuf
DOI:10.1002/anie.200805531
日期:——
5‐Disubstituted furans can be prepared from terminal alkynes in one pot using two successive catalytic reactions (see scheme; p‐TSA=para‐toluenesulfonic acid). First, a 1,3‐dienyl alkyl ether is produced by the dimerization of a terminal alkyne and addition of an alcohol catalyzed by [RuCp*(NCMe)3][PF6]. Then, consecutive hydrolysis and cyclization catalyzed by CuCl2 provides the 2,5‐disubstituted furan.
A general and practical synthetic method for aryl-substituted five-membered heterocycles has been developed. In the presence of KOH (30%), 1,4-diaryl-1,3-butadiynes undergo the cyclocondensation reaction with water, primary amines, and Na2S·9H2O in DMSO at 80 °C to afford 2,5-diarylfurans, 1,2,5-trisubstituted pyrroles, and 2,5-diarylthiophenes in good to high yields. Further studies have disclosed