Heterogeneous manganese-oxide-catalyzed successive cleavage and functionalization of alcohols to access amides and nitriles

Abstract

•Amidation and cyanation of alcohols via successive cleavage of C–C bonds •Amorphous manganese oxide as catalyst and oxygen as oxidant •Wide substrate scope and application to late-stage functionalization •A significant advancement in developing heterogeneous catalyst for lignin valorization The successive cleavage and functionalization of C–C bonds in alcohols has become a rapidly growing field for the discovery of new transformations. However, achieving it in a direct and selective manner remains challenging because of the intrinsic inertness of C–C bonds. Herein, we report a novel and efficient protocol that enables the direct synthesis of amides via heterogeneous manganese-oxide-catalyzed successive cleavage and amidation of C–C bonds in alcohols. A wide range of primary and secondary alcohols, 1,2-diols, and even β-O-4 and β-1 lignin model compounds can undergo C–C bond cleavage smoothly to deliver one- or multiple-carbon shorter amides. Moreover, a slight modification of reaction conditions allows for the cleavage and cyanation of alcohols to access sterically hindered nitriles. Detailed characterizations and density functional theory (DFT) calculations indicate that high specific surface area, abundant oxygen vacancies, and moderate acid sites contribute to the high catalytic performance of the manganese oxides. The successive cleavage and functionalization of C–C bonds in alcohols has become a rapidly growing field for the discovery of new transformations. However, achieving it in a direct and selective manner remains challenging because of the intrinsic inertness of C–C bonds. Herein, we report a novel and efficient protocol that enables the direct synthesis of amides via heterogeneous manganese-oxide-catalyzed successive cleavage and amidation of C–C bonds in alcohols. A wide range of primary and secondary alcohols, 1,2-diols, and even β-O-4 and β-1 lignin model compounds can undergo C–C bond cleavage smoothly to deliver one- or multiple-carbon shorter amides. Moreover, a slight modification of reaction conditions allows for the cleavage and cyanation of alcohols to access sterically hindered nitriles. Detailed characterizations and density functional theory (DFT) calculations indicate that high specific surface area, abundant oxygen vacancies, and moderate acid sites contribute to the high catalytic performance of the manganese oxides.