1: allyltributylstannane With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.5 h; 2: With copper(l) iodide in tetrahydrofuran; hexane T=-78 - -30°C; 0.75 h; 3: but-2-ynoic acid 9H-fluoren-9-ylmethyl ester in tetrahydrofuran; hexane T=-78°C; 0.25 h;

1.1: 96 percent / CSA / benzene / 24 h / Heating 2.1: n-BuLi / tetrahydrofuran; hexane / 0.5 h / -78 °C 2.2: CuI / tetrahydrofuran; hexane / 0.75 h / -78 - -30 °C 2.3: 97 percent / tetrahydrofuran; hexane / 0.25 h / -78 °C View Scheme