# Acridane[4]Arenes: Scope of the Macro‐Tetramerization, Derivatization Options, and Water‐Soluble Derivatives

## TL;DR

Acridane[4]arenes are a new type of macrocycle that can be modified in various ways to create water-soluble structures useful for supramolecular chemistry.

## Contribution

The paper introduces acridane[4]arenes as a modular macrocyclic platform with expanded functionalization options and water-soluble derivatives.

## Key findings

- Acridane[4]arenes can be synthesized in six steps with good yields and conformational stability.
- Selective functionalization and N-Boc modification enable self-assembly into dimeric cages that bind tetrabutylammonium salts.
- Water-soluble derivatives are achieved through ionic substituents like 1-methylimidazolium.

## Abstract

Macrocycles are essential scaffolds in supramolecular chemistry, offering versatile platforms for functionalization. Here, we report the optimization, expanded scope, and comprehensive derivatization strategies for acridane[4]arenes (A4A), a large macrocyclic platform featuring a conformationally restricted bowl shape analogous to resorcin[4]arene. The scope of the macrocyclization was expanded with four distinct ‘feet’ substituents at the lower rim. Strategies for selective functionalization at the upper rim were developed, including N‐Boc protection at each acridane subunit. This modification induced self‐assembly into a dimeric cage in apolar solvents, which form stable host–guest complexes with tetrabutylammonium salts. Further functionalization of the acridane nitrogen via Buchwald–Hartwig cross‐coupling allowed installation of aromatic groups bearing diverse functional handles. Finally, water‐soluble A4A derivatives were achieved by introducing charged ionic ‘feet’ substituents, such as 1‐methylimidazolium. These results establish A4As as a highly modular macrocyclic platform with broad potential for supramolecular applications.

Acridane[4]arenes (A4As) are introduced as a versatile, conformationally restricted macrocyclic platform accessible in six steps and good yields. Expanded lower‐rim scope, selective upper‐rim functionalization, and N‐Boc modification enable controlled self‐assembly into a dimeric cage that binds tetrabutylammonium salts. Further Buchwald–Hartwig diversification and ionic substituents afford water‐soluble derivatives, establishing A4As as a broadly modular scaffold for supramolecular applications.