1.1: 77 percent / boron trifluoride etherate / tetrahydrofuran; cyclohexane / -78 - -5 °C 2.1: 97 percent / imidazole / dimethylformamide / 0 - 20 °C 3.1: N-methylmorpholine N-oxide; OsO4 / 2-methyl-propan-2-ol; tetrahydrofuran; H2O / 3 h / 20 °C 4.1: 145 mg / K2CO3; Pb(OAc)4 / benzene / 5.5 h / 20 °C 5.1: 18-crown-6-ether; KN(TMS)2 / toluene; tetrahydrofuran / 0.08 h / -78 °C 5.2: 208 mg / tetrahydrofuran; toluene / 3 h / -78 °C 6.1: 92 percent / DIBAL-H / tetrahydrofuran; hexane / 1 h / -78 °C 7.1: 97 percent / DMSO; oxalyl chloride / CH2Cl2 / 0.5 h / -78 °C 8.1: toluene / 12 h / Heating 9.1: 83 percent / NaBH4; sulfur / tetrahydrofuran / 5 h / Heating 10.1: LiOH; H2O / methanol; tetrahydrofuran / 48 h / 20 °C 11.1: 81 percent / diisopropylethylamine; bis(2-oxo-3-oxazolidinyl)phosphinic chloride / toluene / 12 h / 85 °C 12.1: 73 percent / tetrabutylammonium fluoride / tetrahydrofuran / 52 h / 20 °C 13.1: CH2Cl2 / 0.17 h / 20 °C 13.2: 97 percent / K2CO3 / methanol / 1.25 h 14.1: 63 percent / aq. ceric ammonium nitrate / acetonitrile / 0.17 h / -10 °C View Scheme