1.1: 83 percent / imidazole / dimethylformamide / 2 h / 20 °C 2.1: 87 percent / DDQ / CH2Cl2; H2O / 0.5 h / 20 °C 3.1: 81 percent / pyridine / CH2Cl2 / 0.17 h / -78 °C 4.1: 9-BBN / tetrahydrofuran / 2 h / 40 °C 4.2: 37 percent / thallium carbonate; triphenylarsine / [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) / tetrahydrofuran; dimethylformamide; H2O / 12 h / 20 °C 5.1: 78 percent / TBAF / tetrahydrofuran / 0.5 h / 0 °C View Scheme