1: (ethyl)-triphenylphosphonium iodide With methyllithium in tetrahydrofuran T=0°C; 1 h; 2: 5-hexenal With methyllithium in tetrahydrofuran Wittig reaction; 3: With tert-butyl alcohol in tetrahydrofuran T=-78 - 20°C; Further stages.;

trifluoroacetic acid T=60°C; 3 h;

1.1: PCC / CH2Cl2 / 5 h 2.1: MeLi / tetrahydrofuran / 1 h / 0 °C 2.2: MeLi / tetrahydrofuran 2.3: t-BuOH / tetrahydrofuran / -78 - 20 °C View Scheme

(dicyclohexylamino)borane T=220 - 235°C;

T=275°C; 6 h; Product distribution; Further Variations:reaction time;