Novel reactions with the underutilized BrF₃: The chemistry with nitriles

Bromine trifluoride is a relatively new reagent in organic and fluoroorganic chemistry. Under the right conditions, it can be a useful tool and generate new types of reactions and compounds. In order to react properly, it has to be complexed by at least two, close in space, electron donating elements, after which it's nucleophilic fluorides can react with nearby potential electrophiles. Thus, it was found that while BrF₃ does not react cleanly with aliphatic nitriles, it can convert them with good yield to a trifluoromethyl group when a neighboring carboxylic moiety is present. BrF₃ attacks also the electrophilic carbonyl carbon transforming it to a difluoroether, but simple hydrolysis regenerates the carboxylic group to give eventually α-trifluoromethyl esters (e.g. 5→6). In the case of the keto nitrile 14, a participation of the internal nucleophilic oxygen in attacking the nitrile carbon was also observed.