1: With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 4 h; 2: With boric acid trimethyl ester in tetrahydrofuran; hexane T=-78 - 20°C; 3: With hydrogenchloride in tetrahydrofuran; hexane T=20°C; 12 h;

1.1: 98 percent / NaH / tetrahydrofuran; hexane / 3 h / 20 °C 2.1: n-BuLi / hexane; tetrahydrofuran / 4 h / -78 °C 2.2: trimethylborate / tetrahydrofuran; hexane / -78 - 20 °C 2.3: aq. HCl / tetrahydrofuran; hexane / 12 h / 20 °C View Scheme