Cyclotrimerization of unsymmetrically bromo-substituted diynes: toward the synthesis of potential selective inhibitors of tyrosine kinase 2

A study on transition metal catalyzed alkyne cyclotrimerization of unsymmetrically bromo-substituted diynes with ethynyltrimethylsilane was carried out to prepare bicyclic bromobenzene key intermediates for the total synthesis of five potential tyrosine kinase 2 inhibitors. Two different pre-catalysts (Cp*RuCl(cod) and [Rh(cod)2]BF4/BINAP) and different reaction conditions have been examined.