1: 95 percent / pyridine / Ambient temperature 2: 72 percent / hydrochloric acid / tetrahydrofuran / 1 h / Heating 3: 66 percent / imidazole / dimethylformamide / 13 h / 60 °C 4: 89 percent / pyridine / 0.5 h / Ambient temperature 5: 90 percent / tetra-n-butylammonium fluoride / tetrahydrofuran / 0.5 h / Ambient temperature 6: 47 percent / 1,1,3,3-tetramethylurea, stannous triflate, 4A molecular sieves / CH2Cl2 / 16 h / Ambient temperature 7: 95 percent / sodium methoxide / methanol / 1 h / Ambient temperature View Scheme

1: 95 percent / diisopropylethylamine / CH2Cl2 / 2 h 2: 80 percent / p-TsOH*H2O / CH2Cl2; methanol / 14 h View Scheme