1: 45.6 percent / imidazole / dimethylformamide 2: 87.6 percent / n-BuLi; BF3.Et2O / tetrahydrofuran / -50 °C 3: 49.4 percent / H2 / Lindlar's catalyst / toluene 4: 82.1 percent / aq. HF / acetonitrile 5: 68.8 percent / lipase PS / aq. phosphate buffer; acetone / pH 7.0 View Scheme