BAr<sup>F</sup><sub>3</sub>‑Catalyzed Imine Hydroboration with Pinacolborane Not Requiring the Assistance of an Additional Lewis Base

Published on 2017-06-19T13:08:49Z (GMT) by
The rarely used boron Lewis acid tris­[3,5-bis­(trifluoromethyl)­phenyl]­borane (BAr<sup>F</sup><sub>3</sub>) is found to be an excellent catalyst for metal-free hydroboration of imines. In the presence of 1.0 mol % of BAr<sup>F</sup><sub>3</sub>, several ketimines and aldimines undergo hydroboration with pinacolborane (HBpin) at room temperature without the aid of an external Lewis base. BAr<sup>F</sup><sub>3</sub> is more reactive than other Lewis acidic boranes, including the often-used tris­(pentafluorophenyl)­borane (B­(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>). The steric hindrance imparted by the six fluorine atoms ortho to the boron center in B­(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub> accounts for this. Mechanistic control experiments indicate conventional Lewis acid catalysis involving imine activation and hydride transfer from HBpin.

Cite this collection

Yin, Qin; Soltani, Yashar; Melen, Rebecca L.; Oestreich, Martin (2017): BArF3‑Catalyzed Imine

Hydroboration with Pinacolborane Not Requiring the Assistance of an

Additional Lewis Base. ACS Publications.

https://doi.org/10.1021/acs.organomet.7b00381

Retrieved: 10:58, Aug 22, 2017 (GMT)