1: With hydrogenchloride T=87°C; 2 h; 2: With methyloxirane in ethanol T=20°C; 0.5 h; Further stages.;

1.1: n-BuLi; diisopropylamine / tetrahydrofuran; hexane / 1.5 h / -30 °C 1.2: hexamethylphosphoric triamide / tetrahydrofuran; hexane / -78 °C 1.3: 82 percent / tetrahydrofuran; hexane / 12 h / -78 °C 2.1: aqueous NaOH / methanol; acetone / 2 h / 20 °C 2.2: 88 percent / aqueous HCl / 3 h / 92 °C View Scheme