Long-Lived Trifluoromethanide Anion: A Key Intermediate in Nucleophilic Trifluoromethylations.
Journal article, 2014
The trifluoromethanide anion is the postulated key intermediate in nucleophilic trifluoromethylation reactions. However, for more than six decades, the trifluoromethanide anion was widely believed to exist only as a short-lived transient species in the condensed phase. It has now been prepd. in bulk for the first time in THF soln. The trifluoromethanide anion with the [K(18-crown-6)]+ cation was unequivocally characterized by low-temp. 19F and 13C NMR spectroscopy. Its intermediacy in nucleophilic trifluoromethylation reactions was directly evident by its reaction chem. with various electrophilic substrates. Variable-temp. NMR spectroscopy, along with quantum mech. calcns., support the persistence of the trifluoromethanide anion. [on SciFinder(R)]