Ru(II)-Catalyzed Chemo- and Regioselective Cyclotrimerization of Three Unsymmetrical Alkynes through Boron Temporary Tether...

The catalytic intermolecular cyclotrimerization of three different unsymmetrical alkynes was accomplished by means of the ruthenium catalysis and the temporary tethering approach with the C-B-O linkage. The crude arylboronates were further applied to the Suzuki-Miyaura coupling with various aryl iodides using Pd2(dba)3/PCy3 as a catalyst precursor in aqueous toluene to afford biaryls. As a result, the novel four-component coupling approach to highly substituted biaryls was successfully established by combining these two operations into a sequential one-pot process.