Synthesis of (MeCN)2Pd(CF3)OTs, a General Precursor to Palladium(II) Trifluoromethyl Complexes LPd(CF3)X

Abstract

In palladium-catalyzed aryl–trifluoromethyl cross-coupling reactions, reductive elimination is often the rate-limiting step. Stoichiometric studies of reductive elimination have proved effective in evaluating the ability of various ligands to facilitate this challenging elementary step. However, the difficulty of synthesizing palladium trifluoromethyl complexes has hindered the use of this strategy. To address this deficiency, we herein report the synthesis of (MeCN)2Pd(CF3)OTs, an air- and moisture-stable solid that can be used as a common precursor to access various LPd(CF3)X complexes. From this complex we were able to prepare palladium trifluoromethyl complexes bearing many monophosphine, bisphosphine, and diamine ligands that are known to help facilitate Ar–CF3 and vinyl–CF3 reductive elimination. Further, we found that the anionic ligand (X) could be readily changed by modifying the NaX or AgX salt used.