IrIII/NiII-Metallaphotoredox catalysis: the oxidation state modulation mechanism versus the radical mechanism

Abstract

A novel oxidation state modulation mechanism, merging oxidative quenching (Ir^III–*Ir^III–Ir^IV–Ir^III) and nickel catalytic (Ni^II–Ni^I–Ni^III–Ni^I–Ni^II) cycles, has been illuminated unambiguously for photoredox-mediated iridium(III)/nickel(II) dual catalyzed C–O cross-coupling of aryl bromide and alcohol. Quinuclidine participates in a crucial proton-coupled electron transfer process to accelerate the reaction and regulate C–O coupling selectivity.