Catalytic Atroposelective Synthesis of C−N Axially Chiral Aminophosphines via Dynamic Kinetic Resolution

Abstract

A ruthenium‐catalyzed reductive amination via asymmetric transfer hydrogenation (ATH) has been used to perform an efficient dynamic kinetic resolution (DKR) of N‐aryl 2‐formyl pyrroles decorated with a phosphine moiety positioned at the ortho’ position. The strategy relies on the labilization of the stereogenic axis in the substrate facilitated by a transient Lewis acid‐base interaction (LABI) between the carbonyl carbon and the phosphorus center. The reaction features broad substrate scope of aliphatic amines and N‐Aryl pyrrole scaffolds, and proceeds under very mild conditions to afford P,N atropisomers in good to high yields and excellent enantioselectivities (up to 99% ee) for both diphenyl and dicyclohexylphosphino derivatives.