1: With oxalyl dichloride; dimethyl sulfoxide in dichloromethane T=-78°C; Swern Oxidation; 1.08333 h; 2: With triethylamine T=0°C; 1.5 h;

1.1: caesium carbonate; copper(l) iodide; tetra-(n-butyl)ammonium iodide / N,N-dimethyl-formamide / 0.33 h / 20 °C 1.2: 24 h 2.1: pyridine; hydrogen / ethyl acetate / 24 h / 20 °C / 760.05 Torr 3.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / 1.08 h / -78 °C 3.2: 1.5 h / 0 °C View Scheme

1.1: caesium carbonate; copper(l) iodide; tetra-(n-butyl)ammonium iodide / N,N-dimethyl-formamide / 0.33 h / 20 °C 1.2: 24 h 2.1: pyridine; hydrogen / ethyl acetate / 24 h / 20 °C / 760.05 Torr 3.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / 1.08 h / -78 °C 3.2: 1.5 h / 0 °C View Scheme

1.1: pyridine; hydrogen / ethyl acetate / 24 h / 20 °C / 760.05 Torr 2.1: oxalyl dichloride; dimethyl sulfoxide / dichloromethane / 1.08 h / -78 °C 2.2: 1.5 h / 0 °C View Scheme