1: 92 percent / oxidation 2: 1.) potassium t-butoxide / 1.) THF, -20 deg C 2h; 2.) THF, -13 deg C, rt 12 h 3: 80 percent / p-toluenesulfonic acid / methanol / 1.) rt 40 min; 2.) 50 deg C 2.5 h View Scheme

copper dichloride in methanol T=20°C; Hydrolysis;

oxidation;

1: 92 percent / oxidation 2: 1.) potassium t-butoxide / 1.) THF, -20 deg C 2h; 2.) THF, -13 deg C, rt 12 h 3: 80 percent / p-toluenesulfonic acid / methanol / 1.) rt 40 min; 2.) 50 deg C 2.5 h 4: pyridine / 1.) 0 deg C; 2.) rt 12 h View Scheme

iron(III) chloride T=20°C; Esterification; 1 h;