A Direct Method to Prepare Zwitterionic Organotrifluoroborates: Ammonium and Sulfonium Derivatives

Organotrifluoroborates are an important functional group that is used in synthesis, diagnostics, and, more recently, in theranostics. Here, we present a practical, one‐step synthesis of ammonium and sulfonium trifluoroborate zwitterionic derivatives by N‐ or S‐ alkylation of bromomethyltrifluoroborate. The reaction proceeds smoothly to produce the desired compounds with good to excellent yields. In particular, the preparation of some sulfonium trifluoroborate derivatives, which avoids the use of expensive or troublesome reagents, their complete spectroscopic characterization, and an example of their application in a click‐chemistry reaction are reported.