Other additives were also tested, starting with LiBF4 which, according to Han, facilitates the cleavage of the C-O bond in aryl methyl ethers. In that case however, the catalytic activity was totally lost even though methyl iodide was still formed (Table ). Switching lithium iodide to use larger cations such as potassium, PPh4 + , or sodium was also deleterious to the catalytic activity, and no conversion was observed (Table , Entries 13, 14 and 15,). Replacing LiI with LiBr allowed the formation of methane in 64 % yield, with only traces of MeBr and MeOH (Table , Entry 12). Such modifications did not improve the catalytic activity further, and we continued to use 3 mol% of 4, together with 20 mol% of LiI, in THF, at 160 °C, for the rest of the study. Incidentally, on this optimized system, when methyl formate and LiI are replaced by a 1:1 mixture of lithium formate and methyl iodide, we observed, after 24 h at 160 °C, a conversion of 78 % and an intense peak of methane in 1 H NMR, confirming our previous mechanistic hypotheses.