C −H Arylation of Thiophenes with Aryl Bromides by a Parts-per-Million Loading of a Palladium NNC-Pincer Complex

Synlett DOI: 10.1055/s-0040-1707213 A palladium NNC-pincer complex efficiently catalyzed the direct arylation of thiophene derivatives with extremely low palladium loadings of the order of parts per million. Thus, the reaction of various thiophenes with aryl bromides in the presence of 25–100 mol ppm of chlorido[(2-phenyl-κ-C
2)-9-phenyl-1,10-phenanthroline-κ2-N,N′]palladium(II) NNC-pincer complex, K2CO3, and pivalic acid in N,N-dimethyl­acetamide afforded the corresponding 2- or 5-arylated thiophenes in good to excellent yields. A combination of the present C–H arylation and Hiyama coupling with the same NNC-pincer complex provides an efficient synthesis of unsymmetrical 2,5-thiophenes with catalyst loadings at mol ppm levels. [...] © Georg Thieme Verlag Stuttgart · New YorkArticle in Thieme eJournals: Table of contents  |  Abstract  |  Full text

Source: Synlett - July 23, 2020 Category: Chemistry Authors: Purta, Anggi Eka Ichii, Shun Tazawa, Aya Uozumi, Yasuhiro Tags: letter Source Type: research