Metal- and Solvent-Free Synthesis of m-Terphenyls by an Iodine-Catalyzed Tandem Formal [3+3]-Cycloaddition/Oxidation

A tandem formal [3+3]-cycloaddition/oxidation between chalcones and beta-enamine esters, employing iodine as a catalyst, was developed for the construction of various substituted m-terphenyls. A wide range of chalcones and beta-enamine esters were tested under metal- and solvent-free conditions for the synthesis of substituted m-terphenyls in good to excellent yields in the presence of sulfur as an oxidant. This reaction proceeds with the formation of four new bonds and one new ring, with a high atom economy.

Automated summary

A new reaction method, employing a metal- and solvent-free [3+3]-cycloaddition/oxidation between chalcones and beta-enamine esters using iodine as a catalyst, was developed for the synthesis of various substituted m-terphenyls.