1.1: sodium hydride / tetrahydrofuran / 0.25 h / 0 °C 1.2: 70 percent / tetrahydrofuran / 1.5 h / 20 °C 2.1: 70 percent / tert-butyl hydroperoxide; n-butyllithium / tetrahydrofuran; toluene; hexane / 2 h / -20 - -10 °C 3.1: 82 percent / LiOtBu / dimethylsulfoxide; tetrahydrofuran / 2 h / 25 °C 4.1: 97 percent / KOtBu / tetrahydrofuran / 2 h / 25 °C View Scheme

1.1: sodium hydride / tetrahydrofuran / 0.25 h / 0 °C 1.2: 70 percent / tetrahydrofuran / 1.5 h / 20 °C 2.1: 70 percent / tert-butyl hydroperoxide; n-butyllithium / tetrahydrofuran; toluene; hexane / 2 h / -20 - -10 °C 3.1: 82 percent / LiOtBu / dimethylsulfoxide; tetrahydrofuran / 2 h / 25 °C View Scheme