Asymmetric Electrophilic Amination of Calix[4]arene Amines: Rapid Assembly of Inherently Chiral Diamine Frameworks

This study reports a chiral phosphoric acid (CPA)-catalyzed asymmetric electrophilic amination of calix[4]arene amines, enabling the first synthesis of inherently chiral diamines with distinctive structural features. The method delivers high reaction productivity (up to 91% yield) and excellent enantioselectivity (up to 99% ee), while exhibiting broad substrate scope (24 examples). The resulting diamines provide versatile platforms for the downstream construction of architecturally diverse, heterocycle-fused chiral calix[4]arenes.