1: OsO4; N-methylmorpholine-N-oxide / tetrahydrofuran; H2O; 2-methyl-propan-2-ol / 120 h / 4 °C 2: pyridine 3: 93 percent / NaBH4 / dimethylformamide / 2 h / 20 °C 4: Bu4NF / tetrahydrofuran / 0.08 h / 20 °C View Scheme

tetrabutyl ammonium fluoride in tetrahydrofuran 2 h;