Palladium/chiral phosphine–olefin complexes: X-ray crystallographic analysis and the use in catalytic asymmetric allylic alkylation

X-ray crystallographic studies on π-allylpalladium complexes coordinated with a chiral phosphine–olefin ligand (−)-1b demonstrate that the phosphine ligand shows a larger trans-influence than the π-bound olefin. The palladium/chiral phosphine–olefin complex efficiently catalyzed asymmetric allylic alkylation of 1,3-diphenyl-2-propenyl acetate with 96% enantioselectivity.

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(−)-(1R,4S,7R)-Spiro[7-diphenylphosphinylbicyclo[2.2.1]heptane-2,2′-[1,3]dioxolane]C21H23O3PEe = >99%[α]D20=-21.5 (c 1.00, CHCl3)Source of chirality: resolution with a chiral HPLC columnAbsolute configuration: (1R,4S,7R)

(−)-(1S,4R,7S)-7-Diphenylphosphinyl-2-trifluoromethanesulfonylbicyclo[2.2.1]hept-2-eneC20H18F3O4PSEe = >99%[α]D20=-32.8 (c 1.00, CHCl3)Source of chirality: resolution with a chiral HPLC columnAbsolute configuration: (1S,4R,7S)

(−)-(1S,4R,7S)-2-Benzyl-7-diphenylphosphinobicyclo[2.2.1]hept-2-eneC26H25PEe = >99%[α]D20=-56.5 (c 0.56, CH2Cl2)Source of chirality: resolution with a chiral HPLC columnAbsolute configuration: (1S,4R,7S)

(−)-(1S,4R,7S)-7-Diphenylphosphino-2-phenylbicyclo[2.2.1]hept-2-eneC25H23PEe = >99%[α]D20=-287 (c 0.40, CH2Cl2)Source of chirality: resolution with a chiral HPLC columnAbsolute configuration: (1S,4R,7S)