Medicinal chemists are increasingly exploring saturated, three-dimensional bioisosteres as alternatives to planar aromatic heterocycles to improve the physicochemical and pharmacological properties of drug candidates. Among these emerging molecular frameworks, 3-azabicyclo[3.1.1]heptanes (3-aza-BCHeps) have attracted growing interest as potential pyridine bioisosteres. However, catalytic enantioselective methods for accessing these chiral nitrogen-bridged scaffolds have remained scarce. Researchers have now developed a chiral Brønsted acid-catalyzed asymmetric transfer hydrogenation that provides efficient access to enantioenriched 3-aza-BCHeps with broad substrate scope and excellent enantioselectivity.
