Synthesis of a π‐Extended Azacorannulenophane Enabled by Strain‐Induced 1,3‐Dipolar Cycloaddition

摘要

Abstract The first example of a cyclophane bearing a nitrogen‐containing buckybowl was synthesized via sequential 1,3‐dipolar cycloaddition and palladium‐catalyzed intramolecular cyclization. The key to the successful synthesis is the strain‐induced 1,3‐dipolar cycloaddition of a polycyclic aromatic azomethine ylide to the K‐region of 7(2,7)pyrenophane. The resulting π‐extended azacorannulenophane exhibits intriguing structural and physical properties, including unique variation of bowl depth, extraordinarily high‐field chemical shifts in its 1H?NMR spectrum, a decreased HOMO–LUMO gap, and a red shift in the absorption/emission spectrum, when compared to those of the parent azacorannulene. These characteristics are derived from both the π‐extension to the polycyclic aromatic system in the cyclophane structure and the increased curvature enforced by the seven‐carbon aliphatic chain.