1: 1,1-dibromo-3,3-dimethyl-dec-5-yn-2-one With lithium hexamethyldisilazane in tetrahydrofuran; hexane T=-78°C; 0.333333 h; 2: With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.5 h; 3: tri-isopropylsylil trifluoromethane sulfonate in tetrahydrofuran; hexane T=-78 - 0°C;