Triazole-Imidazole (TAIM) as Novel Fluorescence Probe for Selective Ag⁺ Cation Detection with PPM Scale

Qi Lai, Teng Yuan, Xiaodong Shi

University of South Florida

A gold catalyzed oxidative alkyne coupling was developed as an efficient approach for the synthesis of challenging cyclic conjugated diyne.  Compared to copper promoted oxidative alkyne coupling, gold complexes gave much faster reaction due to a faster reductive elimination from Au(III) intermediates.  This unique reactivity allowed macrocyclization under dilute conditions with good overall reactivity.  Condition screening revealed crucial combination of [(n-Bu)₄N]⁺[Cl-Au-Cl]^-  as the catalyst and Phen-ligand for successful relativities.   Ring structures with size between 14 to 20 atoms were prepared in good to excellent yields while copper catalysts gave poor results, which highlighted the unique advantage of this new strategy.