Polymer Support Assisted Selective Functionalization of Azoles Using a Palladium-Catalyzed Coupling Reaction
作者:Yoshinori Kondo、Takashi Komine、Takao Sakamoto
DOI:10.1021/ol000183u
日期:2000.10.1
Regioselective palladium-catalyzed monoarylation of azoles was achieved using iodobenzoate immobilized on an insoluble polymer support. The positional selectivity for the coupling reaction was dramatically influenced by the presence of CuI. No diarylation was observed in either case. Unsymmetrical diarylation was also obtained with the polymer support using sequential coupling reactions.
Antibacterial compounds of formula (I) are provided:
as well as stereoisomers, pharmaceutically acceptable salts, esters, and prodrugs thereof; pharmaceutical compositions comprising such compounds; methods of treating bacterial infections by the administration of such compounds; and processes for the preparation of such compounds.
In contrast, the use of aromatic solvents as the reaction medium for directarylations, although some of them show good EHS values, is poorly reported, probably due to their low solvent power against reagents and their potential involvement in undesired side reactions. In this paper we report an unprecedented selective C-5 arylation procedure involving anisole as an EHS green reaction solvent. In addition
Sterically Encumbered Tetraarylimidazolium Carbene Pd-PEPPSI Complexes: Highly Efficient Direct Arylation of Imidazoles with Aryl Bromides under Aerobic Conditions
作者:Xu-Xian He、Yinwu Li、Bei-Bei Ma、Zhuofeng Ke、Feng-Shou Liu
DOI:10.1021/acs.organomet.6b00391
日期:2016.8.22
A series of sterically encumbered tetraarylimidazolium carbene Pd-PEPPSI complexes were conveniently prepared and fully characterized. These sterically encumbered Pd-PEPPSI complexes act as active precatalysts for the direct arylation of imidazoles with aryl bromides under aerobic conditions. The catalytic performance of Pd-PEPPSI complexes in cross-coupling processes is investigated. Under the optimal protocols, the cross-coupling reactions regioselectively produced C5-arylation products in moderate to excellent yields, which could tolerate a wide range of functional aryl bromides.