Investigation of Steric and Electronic Features of 3‑Iminophosphine-Based Palladium Catalysts for Intermolecular Hydroamination

A series of (3-iminophosphine)­allylpalladium triflate
complexes
with systematic variation of both steric and electronic features was
isolated and characterized. The ability of the complexes in this series
to catalyze the regioselective hydroamination of 3-methyl-1,2-butadiene
with aryl amines to form solely the kinetic product was probed by
observing conversion to products via NMR spectroscopy. The previously
unstudied 3-iminophosphine ligand composed of a di-tert-butyl phosphine, cyclobutene backbone, and tert-butyl imine provided the most active palladium hydroamination catalyst
for this transformation known to date.