Anhydrous tetrabutylphosphonium hydrogen bifluoride (2), dihydrogen trifluoride prepared from aq. tetrabutylphosphonium hydroxide and aq. HF, and tetrabutylphosphonium fluoride prepared from 2 and Bu n Li were shown to be useful fluoride sources for selective nucleophilic fluorination of oxiranes, alkyl halides, alcohols and sulfonates of aliphatic and steroidal species.
