Iridium-Catalyzed Hydroarylation via C-H Bond Activation

Hydroarylation reactions via C-H activation, which compensate for shortcomings of classical methods based on the Friedel-Crafts reaction, is one of the most attractive methods to synthesize substituted arenes. This Personal Account reviews our recent studies on iridium-catalyzed intermolecular hydroarylation of vinyl ethers, alkynes, bicycloalkenes, and 1,3-dienes, and intramolecular hydroarylation of m-allyloxyphenyl ketones, where asymmetric addition reactions are included. A cationic iridium catalyst, which is generated from chloroiridium [IrCl] and NaBAr4F [Ar-F=3,5-(CF3)(2)C6H3], or a hydroxoiridium [Ir(OH)] complex is effective in catalyzing the hydroarylation depending on the substrates. 1,5-Cyclooctadiene (cod), chiral dienes, and conventional bisphosphines function as ligands controlling the high reactivity and selectivity of the catalysts in the hydroarylation. H/D exchange reaction of alkenes by use of a key intermediate of the hydroarylation reaction is also described.

Automated summary

Hydroarylation reactions using C-H activation to synthesize substituted arenes can compensate for drawbacks of classical methods like Friedel-Crafts reactions. This method involves iridium-catalyzed intermolecular and intramolecular hydroarylation reactions, including asymmetric addition reactions, depending on substrates. It utilizes a cationic iridium catalyst and various ligands to control reactivity and selectivity, along with a described H/D exchange reaction for alkenes.