A plausible reaction mechanism for the hydrodefluorination of fluoroarenes involves (i) s-bond metathesis between Et3SiH and the group 13 fluoride 1-M forming the group 13 hydride complex and (ii) nucleophilic attack of the hydride on the fluorinated arene by a cSNAr mechanism, liberating the hydrodefluorinated product and regenerating the group 13 fluoride (M= Al, Ga). We have previously shown that a b-diketiminate stabilized aluminum dihydride complex is an effective reagent for the hydrodefluorination of electron-deficient arenes under forcing conditions. Further experiments and calculations were undertaken to shed light on the role of NaBAr after 6 h at 80 °C (Figure ). The expected kinetic product of this reaction 6-Ga was shown to be in equilibrium with 1-Ga and 7-Ga at 25 ºC in fluorobenzene (figure ). DFT calculations support a role of NaBAr F 4 lowering the barrier for metathesis through fluoride coordination (Figure ).