reaction of pinacolborane with various aryl bromides in the presence of a catalytic amount of Pd(OAc)(2) together with DPEphos as ligand and Et(3)N as base provided arylboronates. High yields were obtained in the case of electron-donor substituted aryl bromides. The direct preparation of arylboronates allowed the one-pot, two-step synthesis of unsymmetrical biaryls in high yields. [reaction: see text]
Synthesis of Biaryls by Decarboxylative Hiyama Coupling
作者:Dmitry Katayev、Benjamin Exner、Lukas J. Gooßen
DOI:10.1002/cctc.201500068
日期:2015.7.13
A trimetallic palladium/copper/silver system has been developed that allows the decarboxylativeHiyamacoupling of ortho‐substituted aryl carboxylates with trialkoxyarylsilanes to give the corresponding biaryls. The cross‐coupling is catalyzed by a Pd/N‐heterocyclic carbene complex with silver carbonate aiding its reoxidation. Copper(II) fluoride acts as decarboxylation catalyst, stoichiometric oxidant