Chiral Ferrocenyl N,N Ligands with Intramolecular Hydrogen Bonds for Highly Enantioselective Allylic Alkylations

Several new ferrocene-derived bidentate N ligands, which contain multiple chiral factors, have been designed and synthesized by a rational combination of oxazoline and pyridine. Their catalytic performances were investigated preliminarily in Pd-catalyzed asymmetric allylic alkylation, and excellent reactivities and enantioselectivities (up to 99% yield and 98% ee) were realized if we used the ligand with a matched chirality. DFT calculations were used to illustrate that an intramolecular hydrogen bond formed between the hydroxyl group and the oxazoline fragment of the ligand contributed to the optimal conformation of the ligand-Pd-allyl complex.