1: SeO2 / ethanol / 2 h / Heating 2: 6.70 g / NaBH4 / methanol / 0.5 h / 0 °C 3: 95.3 percent / CBr4; polymer-supported triphenylphosphine / CH2Cl2 / 4 h / 0 °C 4: 85.3 percent / t-BuOK / tetrahydrofuran; dimethylformamide / 2.5 h / -40 - 20 °C 5: 77 percent / naphthalenyllithium / tetrahydrofuran / 2 h / -78 °C View Scheme