Cu‐Mediated C7 Acetoxylation of Indolines

Transition‐metal‐catalyzed acetoxylation or hydroxylation of arene C−H bonds is regarded as a valuable transformation in organic synthesis for the efficient incorporation of oxygen atoms. [1] This mode of C−H oxidation has received much attention due to the important applications of phenol derivatives in natural products, pharmaceuticals, organic synthesis, metal ligands and materials science. Early discoveries for arene C−H oxidation were generally limited due to poor selectivity, low efficiency and harsh conditions. [3] Strategie that rely coordinating directing groups have enabled the direct oxidation of a specific arene C−H bond with high regioselectivity and efficiency. This methods generally employ palladium (II) or ruthenium (II) catalysts and PhI(OAc) 2 or other stoichiometric oxidants under acidic conditions (Scheme , 1a). Methods using other transition metals, such as a rhodium (III) catalyzed ortho ‐C−H acetoxylation or hydroxylation, have also been reported.