Rearrangements in allylpalladium complexes with hemilabile chelating ligands

In addition to η³- to η¹-allyl rearrangement, η²- to η¹-chelating-ligand rearrangements can affect the dynamic properties in allylpalladium complexes containing hemilabile ligands. These rearrangements have the potential of altering stereochemistry, which can ultimately affect the stereochemistry and regiochemistry of reactions upon the allyl group, e.g., allylic alkylation. Apparent rotation of an η³-allyl in four-coordinate Pd¹¹-complexes can be the result of ligand exchange or intramolecular processes. NMR Studies indicate that the effects of η²- to η¹-chelating-ligand stereochemistry and rearrangements may be hidden or subtle, and both intra- and intermolecular processes may be important.