Copper-Free One-Pot Sonogashira-Type Coupling for the Efficient Preparation of Symmetric Diarylalkyne Ligands for Metal-Organic Cages**

The often time-consuming and challenging multi-step synthesis of ligands for metal-organic cages is a limiting factor for the discovery and application of new cages. We report a highly efficient copper-free one-pot Sonogashira-type coupling for the preparation of symmetric diarylalkyne ligands on both a small and large scale; bipyridine- and benzimidazole-based ligands for the self-assembly of Co4L6 cages were synthesized in short reaction times and high isolated yields directly from aryl halide precursors. This one-pot method reduces the synthetic burden of ligand synthesis and will facilitate the preparation of ligands with additional functionality for applications of their corresponding cages.

Automated summary

The synthesis of ligands for metal-organic cages is often time-consuming and challenging, hindering the discovery and application of new cages. A highly efficient copper-free one-pot Sonogashira-type coupling method has been developed to synthesize symmetric diarylalkyne ligands for Co4L6 cages directly from aryl halide precursors. This method simplifies ligand synthesis and enables the preparation of functionalized ligands for various applications.