1: 3-bromo-5-trimethysilyltoluene With lithium diisopropyl amide in tetrahydrofuran T=-75 - -70°C; 0.5 h; 2: N,N-dimethyl-formamide in tetrahydrofuran T=-70°C; 3: With sulfuric acid in tetrahydrofuran; water

silver trifluoromethanesulfonate in dichloromethane T=20°C; 1.5 h; Inert atmosphere;