1.1: boron trifluoride diethyl etherate / dichloromethane / 0.37 h / -15 °C 2.1: caesium carbonate / dimethyl sulfoxide / 0.25 h / 80 °C 2.2: 0.33 h / 80 °C View Scheme

1.1: boron trifluoride diethyl etherate / dichloromethane / 0.37 h / -15 °C 2.1: caesium carbonate / dimethyl sulfoxide / 0.25 h / 80 °C 2.2: 0.33 h / 80 °C 3.1: phosphoric acid / ethyl acetate; ethanol / 2 h / 50 °C View Scheme

sodium azide; lithium chloride in N,N-dimethyl-formamide T=80°C; 3 h; regioselective reaction;