Aliphatic fluorine–chlorine exchange reactions can be performed under microwave conditions using TREAT-HF as a mild and selective fluorination reagent. The highly polar TREAT-HF couples efficiently with microwave irradiation and reaction temperatures of 250° C can be reached within 30s. Under these conditions dichloromethyl-and trichloromethyl substrates can be converted into the corresponding fluoro analogs within 5min. In order to ...