1.1: trifluoroacetic acid / toluene / 2 h / 20 °C 2.1: potassium hydroxide / ethanol; water / 36 h / 20 °C 2.2: pH Ca. 5 / Cooling with ice 3.1: iodine; dimethyl sulfoxide / 12 h / 110 °C 4.1: palladium 10 on activated carbon; hydrogen / tetrahydrofuran; methanol / 3 h / 20 °C View Scheme

1.1: trifluoroacetic acid / toluene / 2 h / 20 °C 2.1: potassium hydroxide / ethanol; water / 36 h / 20 °C 2.2: pH Ca. 5 / Cooling with ice 3.1: iodine; dimethyl sulfoxide / 12 h / 110 °C 4.1: palladium 10 on activated carbon; hydrogen / tetrahydrofuran; methanol / 3 h / 20 °C View Scheme

1: With MgBr2(Et2O) in diethyl ether T=20°C; 14 h; 2: With hydrogenchloride in diethyl ether; water T=0°C;