1.1: 4-(N,N-dimethlyamino)pyridine; triethylamine; methanesulfonyl chloride / dichloromethane / 1.5 h 1.2: 1 h / 70 °C 2.1: sodium periodate; water / ruthenium trichloride / acetonitrile / 5 h / 0 °C 3.1: N,N-dimethyl-formamide; water / 0.25 h 3.2: 0.17 h / 10 °C 3.3: 1 h / 0 °C 4.1: triphenylphosphine / tetrahydrofuran / 2 h / 50 °C 4.2: 10 h View Scheme