Regioselectivity and memory effects in palladium catalyzed allylic alkylations with bidentate P^PS donor ligands

A series of complexes, [Pd(η3-C3H5)(P^PS)][SbF6], where P^PS are bidentate bisphosphine monosulfide ligands, were found to catalyze allylic alkylation reactions with high branched:linear selectivity with some ligands. Some of these catalysts also display a regiochemical memory effect, in which the hemilability and rigidity of the P^PS ligands affect the reaction rate and the degree to which a memory effect is observed.

Graphical abstractA series of complexes, [Pd(η3-C3H5)(P^PS)][SbF6], where P^PS are bidentate bisphosphine monosulfide ligands, were found to catalyze allylic alkylation reactions with high branched:linear selectivity with some ligands. Some of these catalysts also display a regiochemical memory effect, in which the hemilability and rigidity of the P^PS ligands affect the reaction rate and the degree to which a memory effect is observed.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► [Pd(η3-C3H5)(P^PS)][SbF6] complexes catalyze the allylic alkylation of carbonates with unusually high selectivity for addition to the substituted allylic terminus. ► P^PS ligands forming larger rings gave increased branched selectivity and furthermore, ligand backbone flexibility increased the rate of the reaction. ► There is a significant memory effect observed with a number of P^PS ligands. ► Low temperatures increased the regioselectivity and the magnitude of memory effects.