Reaction of N-Cyanotrialkylammonium Fluorborates and Carboxylic Acids

Since the preparation of stable N-cyanotrialkylammonium fluoroborates (1)^2,3 we have been examining the reactions of the salts with a variety of nucleophiles. We wish to report the reactions of the salts with carboxylic acids. In principle there are two pathways for reaction with a nucleophile. Path A, the alkylation reaction, has been known for a long time and is the basis of the von Braun reaction.^4–6 Path B, the cyanation reaction, has been observed or postulated to occur in a few cases in the reaction of cyanogen halides and acids.^6–7