1.1: LDA / tetrahydrofuran; cyclohexane / 1 h / -78 - 20 °C 1.2: 49 percent / I2 / CH2Cl2 / 0.5 h / 20 °C 2.1: 89 percent / H2; Lindlar catalyst / hexane 3.1: 63 percent / TBAF / tetrahydrofuran / 15 h / 0 °C View Scheme

1: 87 percent / benzene / 2 h / 60 °C 2: HMPA / tetrahydrofuran / 0.5 h / -78 °C 3: 85 percent / H2; Lindlar catalyst / hexane; pyridine / 36 h 4: 84 percent / pyridinium p-toluenesulfonate / methanol / 1.5 h / 20 °C 5: 85 percent / 1N LiOH; CO2 / methanol; tetrahydrofuran / 2.5 h / 0 °C View Scheme