A Thermally Stable, Alkene-Free Palladium Source for Oxidative Addition Complex Formation and High Turnover Catalysis

Oxidative addition complexes play a crucial role in Pd-catalyzed transformations. They are not only key catalytic intermediates, but are also powerful and robust precatalysts, and effective reactants for late-stage functionalization of complex molecules. However, accessing a given oxidative addition complex is often challenging due to a lack of effective and stable palladium sources with the correct reactivity. Herein, we report an easily prepared and bench stable Pd(II) dialkyl complex, DMPDAB–Pd–BTSM (BTSM = bis[trimethylsilylmethyl]), that is a versatile precursor for generating Pd(II) oxidative addition complexes, and a highly active Pd source for in situ catalyst formation in cross-coupling reactions. A crucial aspect of this structure is the absence of alkene-based stabilizing ligands common to other Pd precursors. We demonstrate the utility of this precursor in the formation of several Pd(II) complexes, including phosphine and diimine-ligated oxidative addition complexes, and in high turnover number catalysis of C–O, Suzuki, and Heck coupling reactions.