1.1: tetra(n-butyl)ammonium hydrogensulfate; sodium hydroxide / water / 3 h / 0 °C 2.1: n-butyllithium / tetrahydrofuran; hexane / 1 h / -78 °C 2.2: 0.5 h / -78 °C 3.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / 0.25 h / -78 °C 3.2: 0 - 20 °C 4.1: silver hexafluoroantimonate; gold(III) chloride / dichloromethane / 0.42 h / 20 °C / Molecular sieve 5.1: chromium(VI) oxide; periodic acid / acetonitrile / 1 h View Scheme

1.1: n-butyllithium / tetrahydrofuran; hexane / 1 h / -78 °C 1.2: 0.5 h / -78 °C 2.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / 0.25 h / -78 °C 2.2: 0 - 20 °C 3.1: silver hexafluoroantimonate; gold(III) chloride / dichloromethane / 0.42 h / 20 °C / Molecular sieve 4.1: chromium(VI) oxide; periodic acid / acetonitrile / 1 h View Scheme

1.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / 0.25 h / -78 °C 1.2: 0 - 20 °C 2.1: silver hexafluoroantimonate; gold(III) chloride / dichloromethane / 0.42 h / 20 °C / Molecular sieve 3.1: chromium(VI) oxide; periodic acid / acetonitrile / 1 h View Scheme

1: silver hexafluoroantimonate; gold(III) chloride / dichloromethane / 0.42 h / 20 °C / Molecular sieve 2: chromium(VI) oxide; periodic acid / acetonitrile / 1 h View Scheme

1.1: copper(l) iodide; tetrakis(triphenylphosphine) palladium(0); triethylamine / 0.5 h 1.2: 4 h / 20 °C 2.1: tetra(n-butyl)ammonium hydrogensulfate; sodium hydroxide / water / 3 h / 0 °C 3.1: n-butyllithium / tetrahydrofuran; hexane / 1 h / -78 °C 3.2: 0.5 h / -78 °C 4.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / 0.25 h / -78 °C 4.2: 0 - 20 °C 5.1: silver hexafluoroantimonate; gold(III) chloride / dichloromethane / 0.42 h / 20 °C / Molecular sieve 6.1: chromium(VI) oxide; periodic acid / acetonitrile / 1 h View Scheme