KOtBu-Promoted Oxidation of (Hetero)benzylic Csp3-H to Ketones with Molecular Oxygen.

An efficient and practical (hetero)benzylic sp3 C-H oxidation method has been developed. Notably, this user-friendly protocol employs inexpensive potassium tert-butoxide (KOtBu) as a promoter and proceeds under mild conditions using oxygen as the oxidant. A large variety of oxidation products were prepared in good to excellent yields. The utility of this "green" methodology was further demonstrated by the scale-up preparation of a biologically valued molecule.