Copper-Catalyzed Enantioselective Synthesis of α-Aminoboronic Acid Derivatives

Optically active α-aminoboronic acids, find widespread application in medicinal chemistry. . Herein, we present a straightforward synthetic strategy based on the enantioselective cross-coupling of readily available racemic α-chloro boronates with carbamates using an earth-abundant copper catalyst with a commercial chiral diamine and a diaryl phosphine as the ligands. These reaction conditions originated from a mechanistic study of a photoinduced system. Mechanistic investigations support that product formation occurs via kinetic resolution of the racemic α-chloro boronate. Moreover, the diaryl phosphine is alkylated by the electrophile under the reaction conditions forming α-phosphino boronates that act as the active ligand during catalysis.