1: 6-ethynyl-6-methylundeca-1,10-diene With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 2: methyl chloroformate in tetrahydrofuran; hexane T=-78 - 20°C;

1.1: 80 percent / K2CO3 / methanol 2.1: n-butyllithium / hexane; tetrahydrofuran / -78 °C 2.2: 90 percent / hexane; tetrahydrofuran / -78 - 20 °C View Scheme

1.1: 80 percent / Dibal-H / diethyl ether; hexane / -70 °C 2.1: 80 percent / K2CO3 / methanol 3.1: n-butyllithium / hexane; tetrahydrofuran / -78 °C 3.2: 90 percent / hexane; tetrahydrofuran / -78 - 20 °C View Scheme

1.1: 83 percent / LiHMDS / tetrahydrofuran / 4 h / -78 - 20 °C 2.1: 80 percent / Dibal-H / diethyl ether; hexane / -70 °C 3.1: 80 percent / K2CO3 / methanol 4.1: n-butyllithium / hexane; tetrahydrofuran / -78 °C 4.2: 90 percent / hexane; tetrahydrofuran / -78 - 20 °C View Scheme