1: 7-ethynyl-7,11-dimethyl-dodeca-1,10-diene With n-butyllithium in tetrahydrofuran T=-78°C; 1.25 h; 2: methyl chloroformate in tetrahydrofuran T=-78 - 20°C;

1.1: 83 percent / K2CO3 / methanol / 3 h / 20 °C 2.1: n-butyllithium / tetrahydrofuran / 1.25 h / -78 °C 2.2: 95 percent / tetrahydrofuran / -78 - 20 °C View Scheme

1.1: 89 percent / DIBAL-H / diethyl ether / 0.5 h / -70 °C 2.1: 83 percent / K2CO3 / methanol / 3 h / 20 °C 3.1: n-butyllithium / tetrahydrofuran / 1.25 h / -78 °C 3.2: 95 percent / tetrahydrofuran / -78 - 20 °C View Scheme

1.1: 78 percent / LiHMDS / tetrahydrofuran / 1 h / 20 °C 2.1: 89 percent / DIBAL-H / diethyl ether / 0.5 h / -70 °C 3.1: 83 percent / K2CO3 / methanol / 3 h / 20 °C 4.1: n-butyllithium / tetrahydrofuran / 1.25 h / -78 °C 4.2: 95 percent / tetrahydrofuran / -78 - 20 °C View Scheme

1.1: 78 percent / LiHMDS / tetrahydrofuran / 1 h / 20 °C 2.1: 89 percent / DIBAL-H / diethyl ether / 0.5 h / -70 °C 3.1: 83 percent / K2CO3 / methanol / 3 h / 20 °C 4.1: n-butyllithium / tetrahydrofuran / 1.25 h / -78 °C 4.2: 95 percent / tetrahydrofuran / -78 - 20 °C View Scheme