1: 97 percent / camphorsulphonic acid / acetone / 16 h / Ambient temperature 2: pyridinium chlorochromate, molecular sieve 3 A / CH2Cl2 / 2 h / Ambient temperature; molecular sieve 3 A 3: sodium borohydride / ethanol / 1 h / 0 °C 4: pyridine / CH2Cl2 / 8 h / -20 °C 5: sodium azide / dimethylformamide / 16 h / Ambient temperature 6: 97 percent / tetrabutylammonium fluoride / tetrahydrofuran / 4 h / Ambient temperature 7: 100 percent / hydrogen / palladium black / methanol / 1 h / Ambient temperature 8: aq. sodium bicarbonate / diethyl ether / 1.5 h / 0 °C 9: 75 percent / pyridinium chlorochromate, molecular sieve 3 A / CH2Cl2 / 1.5 h / Ambient temperature 10: 59 percent / CH2Cl2 / 16 h / Ambient temperature 11: 61 percent / hydrogen / palladium black / methanol / 48 h 12: H2 / palladium black / acetic acid / 72 h / Ambient temperature 13: 74 percent / trifluoroacetic acid / D2O / 50 h / Ambient temperature View Scheme

1: sodium hydride / N,N-dimethyl-formamide; mineral oil / 0 - 20 °C 2: tetrabutyl ammonium fluoride / tetrahydrofuran / 20 °C View Scheme