1: 84 percent / DMAP; TEA / CH2Cl2 / 20 °C 2: 100 percent / imidazole / dimethylformamide / 20 °C 3: 100 percent / 1.5M HCl / ethanol / 2 h / 20 °C 4: 59 percent / Ph3P; DEAD / CH2Cl2; toluene / 48 h / 0 °C 5: 100 percent / H2 / 5 percent Pd/C / ethanol / 24 h / 20 °C 6: 90 percent / TBAF / tetrahydrofuran / 20 °C 7: 1.0M LiOH aq. / ethanol / 2 h / 20 °C View Scheme

1.1: 84 percent / DMAP; TEA / CH2Cl2 / 20 °C 2.1: 100 percent / imidazole / dimethylformamide / 20 °C 3.1: 100 percent / 1.5M HCl / ethanol / 2 h / 20 °C 4.1: 59 percent / Ph3P; DEAD / CH2Cl2; toluene / 48 h / 0 °C 5.1: 100 percent / H2 / 5 percent Pd/C / ethanol / 24 h / 20 °C 6.1: 90 percent / TBAF / tetrahydrofuran / 20 °C 7.1: 1.0M LiOH aq. / ethanol / 2 h / 20 °C 8.1: 2M HCl / dioxane / 19 h / 20 °C 8.2: TEA / ethanol View Scheme