Efficient Hydrolysis of Organotrifluoroborates via Silica Gel and Water

A general, mild, and efficient method for the hydrolysis of organotrifluoroborates to unveil boronic acids using silica gel and H(2)O was developed. This method proved to be tolerant of a broad range of aryl-, heteroaryl-, alkenyl-, and alkyltrifluoroborates as well as structurally diverse aminomethylated organotrifluoroborates. As anticipated, electron-rich substrates provided the corresponding boronic acids more readily than electron-poor substrates, owing to the resonance-stabilized difluoroborane intermediate. The method developed was expanded further for the conversion of organotrifluoroborates to the corresponding boronate esters.