It has long been known that alkenes undergo isomerization—both positionally and stereochemically (E/Z)—in the presence of a palladium(II) catalyst, but the mechanistic details of this process have remained murky. In collaboration with the Blackmond lab at Scripps Research, we interrogated the mechanism of E/Z isomerization of alkenyl amides bearing an 8-aminoquinoline (AQ) directing group, which facilitates detection and characterization of otherwise short lived intermediates and suppresses positional isomerization. By leveraging a battery of techniques including in situ monitoring of intermediates, reaction kinetics, deuterium labeling, and DFT calculations, we were able to rule out several mechanistic hypotheses, with the pointing to a monometallic nucleopalladation mechanism. Congrats to Rei, Malkanthi, Mingyu, and high school intern Nhi on this work!
For a link, click here: https://chemrxiv.org/articles/preprint/Mechanistic_Studies_of_Pd_II_-Catalyzed_E_Z_Isomerization_of_Unactivated_Alkenes_Evidence_for_a_Monometallic_Nucleopalladation_Pathway/13194932