1.1: NaN(TMS)2 / tetrahydrofuran / 0.5 h / 20 °C 1.2: 84 percent / tetrahydrofuran / -70 - 20 °C 2.1: 95 percent / TBAF / tetrahydrofuran / 5 h / 20 °C 3.1: 93 percent / PCC / CH2Cl2 / 3 h / 20 °C 4.1: LDA / tetrahydrofuran; hexane / 0.33 h / -78 °C 4.2: tetrahydrofuran; hexane / 0.33 h / -78 °C 4.3: Et3N / CH2Cl2 5.1: 92 percent / DDQ / CH2Cl2; H2O / 0.75 h / cooling 6.1: 92 percent / PCC / CH2Cl2 / 2.5 h / 20 °C 7.1: 93 percent / 2-methyl-2-butene; NaClO2 / 2-methyl-propan-2-ol; H2O; various solvent(s) / 3 h / 20 °C View Scheme