1.1: 91 percent / H2 / Lindlar's catalyst / methanol / 10 h / 20 °C / 760 Torr 2.1: 86 percent / MnO2 / toluene / 1 h / 20 °C 3.1: 95 percent / NBS / dimethylformamide / 0.5 h / 0 °C 4.1: t-BuLi / tetrahydrofuran; pentane / 0.5 h / -78 °C 4.2: 89 percent / tetrahydrofuran; pentane / 1.5 h / -78 - 0 °C View Scheme

1: 86 percent / hydrogen / Lindlar catalyst / methanol / 0.5 h / 760.05 Torr 2: 90 percent / trifluoroacetic acid / toluene / 0.17 h / 150 °C / microwave irradiation View Scheme