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

Abstract

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.