A Low-cost Manganese Complex Catalyst for Phenolic Coupling and Further Oxidation of Phenols

Abstract

Binuclear manganese (Mn) complexes have been prepared as selective oxidants. Here, the oxidativecoupling of phenols under manganese (Mn)-catalyzed conditions were described to form biphenols,ortho-quinones and benzoxepines. Manganese(III) picolinate (Mn (III) (PIC)3 H2O, complex (1) is used asa low- cost and easy to prepare catalyst which activates by periodic acid and some organic substrates canbe oxidized after the activation process proposing that the manganese is converted to a higher oxidationstate. In this study, catalytic oxidation reactions from a mononuclear Mn complex can be used to performmanganese catalysis that usually requires a binuclear complex. The formation of biphenols wassuccessfully determined by using 1HNMR.