Trifluoromethyl ethers R-OCF3 are easily synthesized from the corresponding
dithiocarbonates R-OCS2Me (R = aryl or primary alkyl) by a reagent system
consisting of 70% HF/pyridine and an N-halo imide. When the reaction is app
lied to R-OCS2Me wherein R = secondary alkyl, tertiary alkyl, or benzylic g
roup, fluorination leading to the corresponding alkyl fluorides R-F is achi
eved, whereas a combination of 50% HF/pyridine and N-bromosuccinimide affor
ds the corresponding trifluoromethyl ethers R-OCF3 (R = secondary).