1: With boron trifluoride diethyl etherate in dichloromethane 2: With hydrogenchloride in diethyl ether

1.1: potassium tert-butylate / dimethyl sulfoxide / 0.5 h / 25 - 30 °C / |Inert atmosphere 1.2: 8 h / 25 °C / |Inert atmosphere 2.1: hydrogen sulfide; sodium hydroxide / water / 2.5 h / 45 °C 3.1: boron trifluoride diethyl etherate / dichloromethane View Scheme

1: hydrogen bromide / acetone; water / 2 h / 0 - 20 °C 2: water / 2 h / 100 - 110 °C / |Green chemistry 3: sodium hydroxide / water / 2 h / 100 °C / |Green chemistry 4: boron trifluoride diethyl etherate / dichloromethane View Scheme

1: hydrogen sulfide; sodium hydroxide / water / 2.5 h / 45 °C 2: boron trifluoride diethyl etherate / dichloromethane View Scheme