Conclusions
The mechanism of the borylation reaction of aryl fluoride assisted by a nickel catalyst and base was unravelled by means of DFT based methods. The presence of the sodium phenolate activates the diboron and modifies the classic cross-coupling mechanism. The reaction starts with the oxidative addition, where the metal catalyst breaks the C-F bond, followed by a cis/trans isomerization. This isomerization is more favourable for the mono-phosphine nickel compounds because steric effects. Then the trans intermediate reacts with the adduct B2nep2/NaOPh forming an stable pre-transmetalation species, which evolves to the first product of this reaction and an intermediate. This last one complex finally undergoes the reductive elimination, generating products and recovering the active catalytic species.
Kinetic modelling of the catalytic cycle taking into account the species involved in the most favourable mechanism only was not enough for reproducing the experimentally reported yield. Additional "off-cycle" equilibria, such as those bis-phosphine/mono-phosphine exchange reactions, showed key role in the overall kinetics.
ioChem-BD tools provided straightforward integration of data into this manuscript. 3D structures were very easily embedded by using the HTML code generated with just "on-click" procedure. The ioChem-BD Reaction Energy Profile Report tool , generated using the plot.ly library, is just another piece aimed at enhancing the accuracy of our current computational catalyst discovery toolbox.