1.1: AD-mix-β; MeSO2NH2 / 2-methyl-propan-2-ol; H2O / 16 h / 0 °C 2.1: KOH / H2O; methanol / 2 h / 60 °C 3.1: 13.52 g / TsOH / CH2Cl2 4.1: 94 percent / imidazole / dimethylformamide / 16 h / 20 °C 5.1: 98 percent / H2; propionic acid / methanol / 16 h 6.1: PCC; Celite / CH2Cl2 / 2 h / 20 °C 7.1: NaHMDS / hexamethylphosphoric acid triamide; tetrahydrofuran / -78 °C 7.2: 76 percent / hexamethylphosphoric acid triamide; tetrahydrofuran / -78 - 20 °C 8.1: 88 percent / tetrabutylammonium fluoride / tetrahydrofuran / 2 h / 20 °C 9.1: 64 percent / Re2O7; 2,6-lutidine / CH2Cl2 / 20 °C 10.1: 94 percent / Et3N / CH2Cl2 / 0.5 h / -30 °C 11.1: 90 percent / TsOH / H2O; methanol / 16 h / 20 °C 12.1: 81 percent / pyridine / 3 h / Heating 13.1: 100 percent / LiAlH4 / diethyl ether / 2 h / Heating 14.1: diisopropylethylamine; DMAP / CH2Cl2 / 6 h / 20 °C 15.1: 508 mg / diisopropylethylamine / CH2Cl2 / 12 h 16.1: 95 percent / tetrabutylammonium fluoride / tetrahydrofuran / 2 h / 20 °C 17.1: 86 percent / I2; Ph3P; imidazole / CH2Cl2 / 1 h / 20 °C 18.1: 85 percent / NaHCO3 / acetonitrile / 36 h / 40 °C 19.1: BuLi / hexane; tetrahydrofuran / 0.25 h / cooling 19.2: 60 percent / tetrahydrofuran; hexane / 0.25 h 20.1: 98 percent / H2 / chlorotris(triphenylphosphine)rhodium(I) / benzene; ethanol / 12 h 21.1: 83 percent / AcCl / methanol; CH2Cl2 / 2 h / 20 °C View Scheme

1: AD-mix-β, methanesulfonamide / 2-methyl-propan-2-ol; H2O / 24 h / 0 °C 2: 1.) aq. KOH, 2.) aq. HCl / 1.) MeOH 3: TsOH / CH2Cl2 / 1 h / Ambient temperature 4: imidazole / dimethylformamide / 16 h / Ambient temperature 5: H2 / Pd/C (10percent) / methanol; propionic acid / 24 h 6: PCC, celite / CH2Cl2 / 2 h 7: 1.) KN(SiMe3)2 / 1.) -78 deg C, 2 h, 2.) THF-HMPA, -78 deg C -> r.t., 16 h 8: Bu4NF / dimethylformamide / 2 h / Ambient temperature 9: 1.) Re2O7, lutidine, 2.) TsOH / 1.) CH2Cl2, 4 h, 2.) dimethoxypropane, acetone, 1 h 10: PPH3, DEAD / benzene / 16 h 12: CH2Cl2 / 1 h / -20 - 0 °C 13: TsOH / methanol; H2O / 16 h / Ambient temperature 14: pyridine / 2 h / 100 °C 15: LiAlH4 / diethyl ether; tetrahydrofuran / 2 h / 0 °C / Heating 17: I2, PPh3, imidazole / CH2Cl2 / 1 h / Ambient temperature 18: NaHCO3 / acetonitrile / 24 h / 45 °C 19: 1.) n-BuLi / 1.) THF, 0 deg C, 0.5 h, 2.) THF, 0 deg C -> room temp., 1 h 20: H2, Rh(PPh3)3Cl / benzene; ethanol / 2 h / Ambient temperature 21: acetyl chloride / methanol; diethyl ether / 6 h / Heating View Scheme