Over the past decade, numerous reports have focused on the development and applications of Cu-mediated C−H functionalization reactions; however, to date, little is known about the Cu intermediates involved in these transformations. This paper details the observation and characterization of Cu II and Cu III intermediates in aminoquinoline-directed C(sp 2 )−H functionalization of a fluoroarene substrate. An initial C(sp 2 )−H activation at Cu II occurs at room temperature to afford an isolable anionic cyclometalated Cu II complex. This complex undergoes singleelectron oxidation with ferrocenium or Ag I salts under mild conditions (5 min at room temperature) to afford C(sp 2 )−C(sp 2 ) or C(sp 2 )−NO 2 coupling products. Spectroscopic studies implicate the formation of a transient diamagnetic Cu III -σ-aryl intermediate that undergoes either (i) a second C(sp 2 )−H activation at Cu III followed by C−C bond-forming reductive elimination or (ii) reaction with a NO 2 − nucleophile and C(sp 2 )−NO 2 coupling.

This report describes the reactions between N-heterocyclic carbene copper(I) fluoroalkyl complexes and aryl halides bearing ortho-directing groups. Pyridine, pyrazole, oxazoline, imine, and ester directing groups are shown to dramatically enhance the reactivity of aryl bromides and chlorides with (IPr)CuI–fluoroalkyl complexes (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene; fluoroalkyl = difluoromethyl and pentafluoroethyl) to afford aryl–fluoroalkyl coupling products. This approach is leveraged to achieve the Cu-catalyzed directed fluoroalkylation of a series of aryl bromide substrates.