Catalytic Asymmetric Nucleophilic Amination and Kinetic Resolution of α-Bromo-acylpyrazoles.

Highly enantioselective nucleophilic amination and kinetic resolution of α-bromo-acylpyrazoles with primary aromatic amine nucleophiles are promoted by a stoichiometric amount of Ag2CO3 and a catalytic amount of a chiral PyIPI ligand. The reaction proceeds via an SN2-type kinetic resolution process, which not only provides access to enantioenriched α-amino amide derivatives (up to 95% ee) but also allows for the recovery of the chiral α-bromo-acylpyrazole starting materials (up to 98% ee).