Multi-step reaction with 5 steps 1: tetrahydrofuran / 20 h / 23 °C2: triphenylphosphine, carbon tetrachloride / CH2Cl2 / 14 h / 23 °C3: 100 percent / 25percent aq. ammonium formate / 10percent palladium/carbon / tetrahydrofuran / 0.5 h / 24 °C4: 3 N hydrochloric acid / ethyl acetate / 0.75 h / 21 °C5: 78 percent / sodium bicarbonate, EDCI / dimethylformamide / 22 h / 21 °C