Copper-Catalyzed Cross-Coupling Reaction between Peroxy-benzofuran-2-ones and Phenol Derivatives for the Synthesis of 3-aryl-3-phenyl-benzofuran-2(3H)-ones

Abstract

Peroxides are indispensable functional groups in organic chemistry that are found in a wide range of natural products and pharmaceutical drugs. Peroxides are capable of undergoing a wide range of chemical changes, including rearrangement reactions, because of their weak O-O bond. In general, peroxides are extensively used as oxidants or additives in many chemical transformations. However, it is not explored as a synthetic intermediate for the cross-coupling reaction. Amongst several heterocycles, the 3-phenyl benzofuran-2-one derivatives can easily undergo peroxidation at the tertiary carbon to form 3-tert butyl peroxybenzofuranone, which was studied for the rearrangement reaction with various amine derivatives in the absence of the catalyst. Nevertheless, the cross-coupling reaction with these peroxides is not explored for C-C bond formation. Here, we have studied the copper-catalyzed cross-coupling reaction between 3-phenyl benzofuran-2-one with phenol derivatives to produce 3,3-diaryl benzofuranone derivative. Functionalization at the quarternary carbon can be a quite challenging task and many naturally occurring compounds that are biologically active, such as rosmadial, yuccaol contain a derivative of 3,3-diaryl benzofuranone. It can be also be an important framework to synthesize to support structure-activity relationship in drug synthesis. Thus, we have synthesized up to eight substrates using this method with good to moderate yields. In order to look into the plausible mechanism for this coupling reaction, a series of experiments were conducted. These experimental results suggest that this reaction involves radical intermediates, and a justifiable mechanism is proposed for the copper catalysed cross-coupling of benzofuranone peroxide and phenols. All these research findings and experimental results, along with the complete characterization data, were presented in this report.