C-C Coupling Enabled by Mn Complexes with Diacyl Peroxides: Alkylation versus Oxygenation

We present another dimension of the reactivity of Mn complexes with peroxides. Contrary to the expected oxidation, Mn(OAc)₂ with diacyl peroxides provides C-H functionalization of imidazole N-oxides by an alkyl fragment via a multistep process. The reaction of peroxide with Mn(II) is proposed to generate the catalytic Mn(IV)/Mn(III) species with a noninnocent carboxylate ligand, which is cleaved to afford an alkyl radical and Mn(III) complex. Further addition of an alkyl radical to the C═N bond of imidazole N-oxide and C-H oxidation led to the target product in 23-89% yields.