Reactivity of 3-(pyrrol-1-yl)thiophenes in Pd-catalysed direct arylations

TETRAHEDRON

卷:71

Article

Smari, Imen^1,2  Youssef, Chiraz²  Ben Ammar, Hamed²  Ben Hassine, Bechir²  Soule, Jean-Francois¹  Doucet, Henri¹ 

[1] Univ Rennes, CNRS, Inst Sci Chim Rennes, UMR 6226,Organometall Mat & Catalyse, F-35042 Rennes, France

[2] Univ Monastir, Fac Sci Monastir, Lab Synth Organ Asymetr & Catalyse Homogene, UR 11ES56, Monastir 5000, Tunisia

关键词: Palladium;    Catalysis;    C-H bond activation;    Thiophenes pyrroles;    Direct arylation;    Aryl halides;   

DOI  :  10.1016/j.tet.2015.03.022

来源: Elsevier

【 摘 要 】

The regioselectivity of the Pd-catalysed direct arylation of 3-(pyrrol-1-yl)thiophene derivatives was investigated. Conditions allowing either the regioselective arylation at C2 or at C5 of the thiophene ring are reported. From methyl 3-(pyrrol-1-yl)thiophene-2-carboxylate using KOAc as the base, DMA as the solvent and only 1 mol % Pd(OAc)(2) catalyst, the target 5-arylated thiophenes were obtained in moderate to good yields with a wide variety of aryl halides; whereas the use of 1-(4-methylthiophen-3-yl)-pyrrole affords the C2-arylated thiophenes. The sequential palladium catalysed 2,5-diheteroarylation of such 3(pyrrol-1-yl)thiophene is also reported allowing the access to thiophenes bearing two different aryl units at C2 and C5. A pyrazole bearing an ester substituent at C4 and a pyrrole substituent at C5 was only arylated at C2 on the pyrrole ring. (C) 2015 Elsevier Ltd. All rights reserved.

【 授权许可】

Free