1: 54 percent / n-BuLi / diethyl ether; hexane / 1.5 h / -78 °C 2: 100 percent / NaH / dimethylformamide / 0 - 20 °C 3: 97 percent / N,N-dimethylbarbituric acid; Pd(PPh3)4 / CH2Cl2 / 2.5 h / Heating 4: 75 percent / Et3N; N,N-dimethylaminopyridine / tetrahydrofuran / 6 h / Heating 5: TBAF / tetrahydrofuran / 24 h / 20 °C 6: 89 percent / diisopropylethylamine / CH2Cl2 / 6 h / -78 °C 7: 72 percent / second generation Grubbs catalyst / toluene / 2 h / Heating 8: DIBAL-H / diethyl ether; hexane / 2 h / -78 °C 9: 52.9 mg / toluene / 3.5 h / Heating 10: TFA / CH2Cl2 / 1.17 h / 0 - 20 °C 11: LiOH; H2O / methanol; tetrahydrofuran / 60 h / 20 °C 12: 6.4 mg / DIPEA; BOPCl / toluene / 37 h / 85 °C 13: CH2Cl2 / 0.67 h / 20 °C 14: K2CO3; MeOH / 1.5 h / 20 °C 15: 2.9 mg / aq. cerium ammonium nitrate / acetonitrile / 1 h / -10 °C View Scheme