A versatile catalyst system for Suzuki–Miyaura syntheses of sterically hindered biaryls employing a cyclobutene-1,2-bis(imidazolium) salt

Abstract

The catalyst system consisting of 3,3′-(3,4-bis(dichloro-methylene)cyclobut-1-ene-1,2-diyl)bis(1-methyl-1H-imidazolium) bis(tetrafluoroborate), Pd(OAc)₂ and NaOtBu in toluene proved to be very effective for a broad variety of Suzuki–Miyaura reactions at room temperature. It is also suited for the synthesis of sterically hindered compounds including 2,6-di-tert-butyl-2′-substituted biaryls at elevated temperatures.