The Origin of Catalytic Benzylic C−H Oxidation over a Redox‐Active Metal–Organic Framework

Selective oxidation of benzylic C−H compounds to ketones is important for the production of a wide range of fine chemicals, and is often achieved using toxic or precious metal catalysts. Herein, we report the efficient oxidation of benzylic C−H groups in a broad range of substrates under mild conditions over a robust metal–organic framework material, MFM‐170, incorporating redox‐active [Cu(2) (II)(O(2)CR)(4)] paddlewheel nodes. A comprehensive investigation employing electron paramagnetic resonance (EPR) spectroscopy and synchrotron X‐ray diffraction has identified the critical role of the paddlewheel moiety in activating the oxidant (t)BuOOH (tert‐butyl hydroperoxide) via partial reduction to [Cu(II)Cu(I)(O(2)CR)(4)] species.