A General Method for Interconversion of Boronic Acid Protecting Groups: Trifluoroborates as Common Intermediates

We have developed a general protocol for the interconversion of diverse protected boronic acids, via intermediate organotrifluoroborates. N-Methyliminodiacetyl boronates, which have been hitherto resistant to direct conversion to trifluoroborates, have been shown to undergo fluorolysis at elevated temperatures. Subsequent solvolysis of organotrifluoroborates in the presence of trimethylsilyl chloride and a wide range of bis-nucleophiles enables the generation of a variety of protected boronic acids.