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Intermolecular versus Intramolecular Palladium‐Catalyzed Direct Arylations between 1‐(2‐Bromobenzyl)imidazoles and Aryl Bromides
Author(s) -
Xu Xiaowen,
Zhao Liqin,
Li Yiqun,
Soulé JeanFrançois,
Doucet Henri
Publication year - 2015
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201500332
Subject(s) - intramolecular force , palladium , aryl , chemistry , intermolecular force , imidazole , catalysis , medicinal chemistry , combinatorial chemistry , organic chemistry , molecule , alkyl
Herein, we report on the sequential palladium‐catalyzed intermolecular followed by intramolecular direct arylations of 1‐(2‐bromobenzyl)imidazoles. We found that, in the presence of 1 mol% palladium acetate and potassium acetate as base, the intermolecular reaction between 1‐(2‐bromobenzyl)imidazole derivatives and electron‐deficient aryl bromides proceeded faster than the intramolecular reaction, allowing us to prepare medium‐size polycyclic imidazoles after a second Pd‐catalyzed intramolecular arylation. These iterative direct arylations allowed the synthesis of fused nitrogen‐containing heterocycles with a 5‐ or 7‐membered‐ring in only two steps. Some reactions have also been performed as a one‐pot procedure using 2 mol% of palladium acetate in the presence of a larger amount of base (3 equiv.).