pyridine; hydrogen fluoride in acetonitrile 3 h;

1: 91 percent / tetrahydrofuran / 5 h / Ambient temperature 2: 91 percent / Et3N, DMAP / CH2Cl2 / 3 h / Ambient temperature 3: 76 percent / CuI*P(OEt)3 / tetrahydrofuran / -40 deg C then 0 deg C, 2 h 4: TBAF / tetrahydrofuran / 3 h / Ambient temperature 5: K2CO3 / methanol / 5 h / Ambient temperature 6: pyridinium dichromate / CH2Cl2 / 24 h / Ambient temperature 7: pyridinium dichromate / dimethylformamide / 24 h / Ambient temperature 8: 67 percent / AcOH, H2O / tetrahydrofuran / 14 h / 40 °C View Scheme

1: DIBAH / toluene / 2 h / -78 °C 2: 91 percent / tetrahydrofuran / 5 h / Ambient temperature 3: 91 percent / Et3N, DMAP / CH2Cl2 / 3 h / Ambient temperature 4: 76 percent / CuI*P(OEt)3 / tetrahydrofuran / -40 deg C then 0 deg C, 2 h 5: TBAF / tetrahydrofuran / 3 h / Ambient temperature 6: K2CO3 / methanol / 5 h / Ambient temperature 7: pyridinium dichromate / CH2Cl2 / 24 h / Ambient temperature 8: pyridinium dichromate / dimethylformamide / 24 h / Ambient temperature 9: 67 percent / AcOH, H2O / tetrahydrofuran / 14 h / 40 °C View Scheme

1: 91 percent / Et3N, DMAP / CH2Cl2 / 3 h / Ambient temperature 2: 76 percent / CuI*P(OEt)3 / tetrahydrofuran / -40 deg C then 0 deg C, 2 h 3: TBAF / tetrahydrofuran / 3 h / Ambient temperature 4: K2CO3 / methanol / 5 h / Ambient temperature 5: pyridinium dichromate / CH2Cl2 / 24 h / Ambient temperature 6: pyridinium dichromate / dimethylformamide / 24 h / Ambient temperature 7: 67 percent / AcOH, H2O / tetrahydrofuran / 14 h / 40 °C View Scheme

1: 65 percent / BF3*OEt2 / tetrahydrofuran / 2 h / -78 - 0 °C 2: 1.) pyridinium toluene-p-sulfonate, 2.) CrO3, acid 4: 1.) n-Bu3SnH, AIBN 5: 61 percent / HF / tetrahydrofuran View Scheme

1: 1.) n-Bu3SnH, AIBN 2: 61 percent / HF / tetrahydrofuran View Scheme