1: Alkaline conditions 2: acetonitrile / 2 h / 20 °C / UV-irradiation; Inert atmosphere; Pyrex filter View Scheme

1: Et3N / 1,2-dichloro-ethane 2: thionyl chloride / CH2Cl2; benzene / 4 h / Ambient temperature 3: 100 percent / tetrahydrofuran / Ambient temperature 4: 1.) methyl triflate, 2.) NaBH4, 3.) oxalic acid View Scheme

1: 1.) t-BuLi / 1.) THF, pentane, -78 deg C, 1 h, 2.) THF, pentane, from -78 deg C to RT, 1 h 2: oxalyl chloride / CH2Cl2 / 5 h 3: Et3N / 1,2-dichloro-ethane 4: thionyl chloride / CH2Cl2; benzene / 4 h / Ambient temperature 5: 100 percent / tetrahydrofuran / Ambient temperature 6: 1.) methyl triflate, 2.) NaBH4, 3.) oxalic acid View Scheme

1: oxalyl chloride / CH2Cl2 / 5 h 2: Et3N / 1,2-dichloro-ethane 3: thionyl chloride / CH2Cl2; benzene / 4 h / Ambient temperature 4: 100 percent / tetrahydrofuran / Ambient temperature 5: 1.) methyl triflate, 2.) NaBH4, 3.) oxalic acid View Scheme