Atropoenantioselective synthesis of heterobiaryl N-oxides via dynamic kinetic resolution

A highly efficient enantioselective construction of heterobiaryl N-oxides was developed. A series of axially chiral heterobiaryl N-oxides were generated via the cascade reaction of aminobenzamides with heterobiaryl aldehydes in the presence of chiral phosphoric acids. A number of atropisomers were afforded in moderate to good yields with excellent enantioselectivities and diastereoselectivities. Preliminary results demonstrate that the heterobiaryl N-oxides can be utilized as efficient chiral ligands in asymmetric catalysis.