1: 380 mg / NaClO2; NaH2PO4 / 2-methyl-propan-2-ol; various solvent(s); H2O / 3 h 2: 55 percent / TBAF / tetrahydrofuran / 10 h / 20 °C 3: 69 percent / N-ethyl-N'-(3-(dimethylamino)propyl)carbodiimide *HCl; DMAP; DMAP*HCl / CHCl3 / 17 h / Heating 4: 96 percent / HF*Py; Py / tetrahydrofuran / 36 h / 0 - 20 °C 5: m-CPBA / CHCl3 / 5 h / -18 °C View Scheme

1: 380 mg / NaClO2; NaH2PO4 / 2-methyl-propan-2-ol; various solvent(s); H2O / 3 h 2: 55 percent / TBAF / tetrahydrofuran / 10 h / 20 °C 3: 69 percent / N-ethyl-N'-(3-(dimethylamino)propyl)carbodiimide *HCl; DMAP; DMAP*HCl / CHCl3 / 17 h / Heating 4: 96 percent / HF*Py; Py / tetrahydrofuran / 36 h / 0 - 20 °C View Scheme

sodium chlorite; sodium dihydrogenphosphate; isobutene in tetrahydrofuran; water; tert-butyl alcohol 1 h; Ambient temperature;