1: Methyltriphenylphosphonium bromide With n-butyllithium in tetrahydrofuran; hexane 2: C20H28O4Si in tetrahydrofuran; hexane T=20°C; Wittig methenylation; 20 h;

1.1: 85 percent / LiAlH4 / tetrahydrofuran / 2 h / 20 °C 2.1: Dess-Martin periodinane / CH2Cl2 / 2 h / 40 °C 3.1: n-BuLi / tetrahydrofuran; hexane 3.2: 780 mg / tetrahydrofuran; hexane / 20 h / 20 °C View Scheme

1.1: Dess-Martin periodinane / CH2Cl2 / 2 h / 40 °C 2.1: n-BuLi / tetrahydrofuran; hexane 2.2: 780 mg / tetrahydrofuran; hexane / 20 h / 20 °C View Scheme

2,6-di-tert-butyl-pyridine; trimethylsilyl trifluoromethanesulfonate in dichloromethane T=20°C; Prins reaction; 18 h;