In addition, increasing the temperature was found to be detrimental since only 35% of 3a was obtained at 50 °C (Table , entry 7). Then, the impact of the trifluoromethylthiolating reagent was investigated. Surprisingly, attempt in switching to the more electrophilic Shen's reagent (Ntrifluoromethylthiosaccharin) resulted in lower efficiency with compound 3a only obtained in 30% yield (Table , entry 8). To our delight, adding one equivalent of cesium fluoride allowed for the formation of the desired product in 75% yield (Table ). Finally, potassium fluoride did not improve the overall efficiency of the process (Table , entry 10).