Possible B-C bonding in the hydroboration of benzonitrile by an external electric field.

Generally, the hydroboration of benzonitrile produces B-N containing compounds. However, an unprecedented B-C bond may be formed in the presence of a suitable external electric field (EEF). In reactions of benzonitrile with borane, when the EEF is oriented parallel to the positive direction (N → C) of the N[triple bond, length as m-dash]C bond, the barriers to Markovnikov hydroboration are decreased gradually, meaning the pathway for generating B-C bonds becomes more favorable. Accordingly, hydroboration could be influenced and its selectivity could be controlled by changing the magnitude and direction of an applied EEF.