1: pyridine 2: pyridinium p-toluenesulfonate / ethanol 3: Cornforth reagent / dichloromethane / Molecular sieve 4: sodium chlorite; sodium dihydrogen phosphate dihydrate; 2-methyl-but-2-ene / tert-butyl alcohol 5: tetrakis(triphenylphosphine) palladium(0) / dichloromethane / 20 h / 20 °C View Scheme