Iridium(I)-salicylaldiminato-cyclooctadiene complexes used as catalysts for phenylborylation

Iridium(I) salicylaldiminato-cyclooctadiene complexes, Ir(–o-O–C6H4–CHdouble bond; length as m-dashN–R)(cod) (R = CH2Ph (1), Ph (2); cod = 1,5-cyclooctadiene), have been prepared, characterized and used as catalysts for arylborylation via C–H activation. With 1 as a catalyst, isolated yields of up to 91% has been achieved for the borylation of benzene by bis(pinacolato)diboron in the presence of tetra-2-pyridinylpyrazine and an ionic liquid. The catalytic system could be recycled for at least three times without loss of activity.