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;

1: 3,3-dimethyl-deca-1,5-diyne With lithium hexamethyldisilazane in tetrahydrofuran T=-78°C; 2: With tBuOOLi in tetrahydrofuran; toluene T=-78 - 0°C; 2.5 h; 3: tri-isopropylsylil trifluoromethane sulfonate in tetrahydrofuran; toluene T=-78 - 0°C;

1.1: 76 percent / LiTMP / tetrahydrofuran; hexane / 0.33 h / -78 °C 2.1: LiHMDS / tetrahydrofuran; hexane / 0.33 h / -78 °C 2.2: n-BuLi / tetrahydrofuran; hexane / 0.5 h / -78 °C 2.3: 92 percent / tetrahydrofuran; hexane / -78 - 0 °C View Scheme