Copper porphyrin-catalyzed cross dehydrogenative coupling of alkanes with carboxylic acids: Esterification and decarboxylation dual pathway

Immobilized Copper Complexes on Coal-Bearing Kaolin for Catalyzing Allylic Ester Synthesis via C(sp3)-H Bond Activation

Copper complexes have attracted significant interest for catalyzing oxidative dehydrogenative carboxylation of alkanes to form esters. Here, we report a heterogeneous catalyst, in which copper complexes are immobilized on coal-bearing kaolin for the synthesis of allylic esters via C(sp3)-H bond activation through cross-dehydrogenation coupling reactions between cyclic alkanes and aromatic carboxylic acids. Systematic optimization of reaction conditions-including catalyst loading, copper content, oxidant, temperature, and reaction time-resulted in a high yield of 71% of allylic ester, comparable to homogeneous transition metal catalysts. The catalyst is easily recoverable via centrifugation and retains its activity over five consecutive reuse cycles. This system demonstrates broad substrate compatibility with various aromatic carboxylic acids and cyclic alkanes. Beyond offering an efficient and reusable catalytic route for allylic ester synthesis, this work highlights the potential of coal-bearing kaolin as a sustainable support material for transition metal catalysis and provides an environmentally benign method for activating inert C(sp3)-H bonds.

Copper Porphyrin-catalyzed C(sp3)-H Activation via Cross Dehydrogenative Coupling: Facile Transformation of Aldehydes to Esters

Copper porphyrin-catalyzed alkane C−H bond functionalization with aldehydes via cross dehydrogenative coupling (CDC) using DTBP oxidant has been firstly described in non-solvents or non-additives system. Different aryl/heteroaryl-carboxilic esters were obtained in good to excellent yields depending on the aldehyde derivatives. This CDC reaction catalyzed by copper porphyrin has the advantages of shorter reaction time, lower reaction temperature and catalyst loading as well as the aerobic reaction atmosphere.