Enantioselective Synthesis of β-Amino Acid Derivatives Enabled by Ligand-Controlled Reversal of Hydrocupration Regiochemistry

A Cu-catalyzed enantioselective hydroamination of alpha,beta-unsaturated carbonyl compounds for the synthesis of beta-amino acid derivatives was achieved through ligand-controlled reversal of the hydrocupration regioselectivity. While the hydrocupration of alpha,beta-unsaturated carbonyl compounds to form alpha-cuprated species has been extensively investigated, we report herein that, in the presence of an appropriate ancillary chiral ligand, the opposite regiochemistry can be observed for cinnamic acid derivatives, leading to the delivery of the copper to the beta-position. This copper can react with an electrophilic aminating reagent, 1,2-benzisoxazole, to provide enantioenriched beta-amino acid derivatives, which are important building blocks for the synthesis of natural products and bioactive small molecules.