Iridium-catalyzed borylation of arenes and heteroarenes via C-H activation*
Tatsuo Ishiyama and Norio Miyaura
Division of Chemical Process Engineering, Graduate School of Engineering, Hokkaido University, Sapporo 060-8628, Japan
Abstract: Direct C-H borylation of aromatic compounds catalyzed by a transition-metal complex was studied as an economical protocol for the synthesis of aromatic boron derivatives. Iridium complexes generated from Ir(I) precursors and 2,2'-bipyridine ligands efficiently catalyzed the reactions of arenes and heteroarenes with bis(pinacolato)diboron or pinacolborane to produce a variety of aryl- and heteroarylboron compounds. The catalytic cycle involves the formation of a tris(boryl)iridium(III) species and its oxidative addition to an aromatic C-H bond.
Keywords: iridium catalyst; arylboron compounds; C-H activation; pinacolborane; bis(pinacolato)diboron.
*Paper based on a presentation at the 12th International Meeting on Boron Chemistry (IMEBORON-XII), Sendai, Japan, 11-15 September 2005. Other presentations are published in this issue, pp. 1299-1453.