1: 96.7 percent / H2 / 10percent Pd-C / ethanol 2: pyridine / 0 °C / several hours 3: NaI, NaHCO3 / acetone / Heating; several hours 4: 1) LDA, / 1) THF-hexane-HMPA, -55 deg C, 30 min, 2) THF-hexane-HMPA, -60 to -5 deg C, 3 h 5: 37 percent / AcOH, H2O / tetrahydrofuran / 24 h / 40 °C View Scheme

Multi-step reaction with 6 steps 1: 98.5 percent / LAH / diethyl ether / 2 h / Ambient temperature2: 1) NaH / 1) THF, reflux, 1.5 h, 2) THF, reflux, several hours3: TsOH, MeOH / 0.5 h / Ambient temperature4: 52 percent / Ph3P, EtO2CN=NCO2Et / tetrahydrofuran / 24 h / Ambient temperature5: 95 percent / N KOH aq / tetrahydrofuran; ethanol / 1 h / Ambient temperature6: imidazole / dimethylformamide / Ambient temperature; several hours