1: With boron tribromide in dichloromethane T=0 - 20°C; 2 h; Inert atmosphere; 2: With water in dichloromethane T=0°C; 0.333333 h; Inert atmosphere;

1.1: caesium carbonate / 1-methyl-pyrrolidin-2-one / 0.5 h / 50 °C / Inert atmosphere 1.2: 2 h / 65 °C / Inert atmosphere 2.1: boron tribromide / dichloromethane / 2 h / 0 - 20 °C / Inert atmosphere 2.2: 0.33 h / 0 °C / Inert atmosphere View Scheme