Regioselectivity in the palladium/(S)-BINAP(S)-catalyzed asymmetric allylic amination:: Reaction scope, kinetics, and stereodynamics

Studies defining the scope of the reaction and understanding the factors controlling the unusual regioselectivity observed in the Pd/{BINAP(S)}-catalyzed allylic amination reaction are presented. Most of the unsymmetrically substituted allylic substrates tested show regioselectivity that is the reverse of that which would normally be expected in Pd-catalyzed systems. Several cationic eta(3)-allylic complexes containing a Pd{BINAP(S)} fragment have been synthesized in an attempt to correlate this behavior with structural features of the ligand and the solution structure of the allylpalladium complex. Notably, allylic amines with an alpha-quaternary carbon center may be prepared with high regioselectivity with this system. Spin-saturation transfer studies (SST) were performed on two (kappa(2)-P,S)Pd-pi-allyl complexes in order to determine relative rates for Pd-eta(3)-eta(1)-eta(3)-allyl interconversions and the hemilabile behavior of the BINAP(S) ligand.