1: pyridine / CH2Cl2 / 1 h / -30 °C 2: 1.) lithium triethyl borohydride; 2.) benzyl chloroformate / 1.) THF, 6 h; 2.) ethylacetate 30 min 3: 1.) 50percent aq. trifluoroacetic acid; 2.) sodium borohydride / 1.) 30 min.; 2.) ethanol, room temp., 1 h. 4: 74 percent / hydrogen / 10percent palladium hydroxide on charcoal / ethanol / 12 h View Scheme

1: pyridine / CH2Cl2 / -30 °C 2: NaN3 / dimethylformamide / 12 h / 60 °C 3: 1.) sodium hydrogen telluride / 2.) pyridine 4: 81 percent / aq. trifluoroacetic acid, sodium borohydride 5: 92 percent / H2 / palladium black / acetic acid View Scheme

1: 1.) aq. trifluoroacetic acid; 2.) barium carbonate, bromine / 1.) 15 min; 2.) dioxane, water, from 0 deg C to room temp., 24 h 2: hydrogen / palladium black / aq. acetic acid / 48 h View Scheme