Modular multidentate phosphine ligands: application to palladium-catalyzed allylic alkylations

Multidentate phosphines were readily obtained by reaction of chiral multidentate amines, prepared via ring opening of (S)-N-tosyl-2-isopropylaziridine with ammonia, primary, and secondary amines, with achiral phosphorus containing building blocks. The phosphines were used in palladium-catalyzed alkylation of rac-3-cyclohexenyl and cyclopentenyl carbonates. The enantioselectivity and reactivity were largely dependent on the structure of the amine core of the ligands. Up to 88% ee was observed in reactions with the six-membered substrate.