Dynamic Ion Speciation during the Hydrolysis of Aryltrifluoroborates

Organotrifluoroborates serve as coupling partners during transmetalation in the Suzuki-Miyaura reaction but require hydrolysis prior to the coupling reaction. Their anionic nature allows study of their hydrolysis by electrospray ionization mass spectrometry (ESI-MS) through real-time monitoring, complemented by pH analysis. The induction period varied according to the borates employed, and a dynamic series of equilibria for numerous ions was observed during hydrolysis. We found that the induction periods and reaction rates were sensitive to the R group of the borates, the shape of the reaction vessel, and stir rate.

Automated summary

Organotrifluoroborates are used as coupling partners in the Suzuki-Miyaura reaction, but require hydrolysis before the coupling reaction. Electrospray ionization mass spectrometry (ESI-MS) allows real-time monitoring of their hydrolysis, complemented by pH analysis. The induction periods and reaction rates during hydrolysis were found to be sensitive to the R group of the borates, the shape of the reaction vessel, and stir rate.