sodium hydride in tetrahydrofuran T=0 - 20°C;

manganese(IV) oxide in dichloromethane 3 h; Ambient temperature;

1.1: 96 percent / NaH / tetrahydrofuran / 0 - 20 °C 2.1: Cp2ZrCl2; n-BuLi / tetrahydrofuran; hexane / -78 - 20 °C 2.2: 88 percent / CuCl / tetrahydrofuran; hexane / 5 h / Heating View Scheme