Given the successful use of the carboxylic acid radical precursor, we next interrogated whether a system using potassium benzyl trifluoroborate (2d) as the radical precursor could be implemented, Figure . Using slightly modified reaction conditions (including increasing the auxiliary loading to account for using 2,6-lutidine as a liquid base), we obtained a yield of 75%. Excited by these results, we verified that the reaction in a mechanochemical environment did not detract from the functional group tolerance of these transformations. Indeed, electron-withdrawing aryl bromides were tolerated well in the coupling with potassium trifluoroborate (75 and 86% yield for the methyl ester (1a) and nitrile (1c) substrates, respectively).