1.1: 63 percent / p-TsOH; 4 Angstroem molecular sieves / benzene / 1 h / Heating 2.1: n-BuLi; diisopropylamine / tetrahydrofuran; hexane / 0.5 h / -15 - 0 °C 2.2: tetrahydrofuran; hexane / 0.5 h / -15 - 20 °C 3.1: MCPBA / hexane / 4 h / 20 °C 3.2: 0.8 g / Et3N*3HF / CH2Cl2 / 2 h / 20 °C 4.1: 88 percent / Dess-Martin periodinane / CH2Cl2 / 1 h / 20 °C 5.1: pyrrolidone hydrotribromide / tetrahydrofuran / 1 h / 20 °C 5.2: 71 percent / LiBr; Li2CO3 / dimethylformamide / 2 h / Heating View Scheme

1.1: HMDS / CH2Cl2 / 4 h / -78 - 20 °C 2.1: MCPBA / hexane / 4 h / 20 °C 2.2: 0.4 g / Et3N*3HF / CH2Cl2 / 2 h / 20 °C 3.1: 94 percent / Dess-Martin periodinane / CH2Cl2 / 1 h / 20 °C View Scheme

1.1: HMDS / CH2Cl2 / 4 h / -78 - 20 °C 2.1: MCPBA / hexane / 4 h / 20 °C 2.2: 0.4 g / Et3N*3HF / CH2Cl2 / 2 h / 20 °C 3.1: 94 percent / Dess-Martin periodinane / CH2Cl2 / 1 h / 20 °C 4.1: pyrrolidone hydrotribromide / tetrahydrofuran / 1 h / 20 °C 4.2: 75 percent / LiBr; Li2CO3 / dimethylformamide / 2 h / Heating View Scheme