Cationic and Homoleptic Copper(I)-Thiazol-2-ylidenes: Highly Reactive Thiazole N-Heterocyclic Carbenes σ-Lewis Acid Catalysts.

Air- and moisture-stable cationic homoleptic Cu(I) thiazol-2-ylidene complexes are developed as highly efficient σ-Lewis acid catalysts, outperforming imidazol-2-ylidenes in the alkynylation of ketones without requiring stoichiometric Cu-acetylides. These complexes exhibit exceptional operational simplicity and robustness, enabling key C-C bond formation. Structural insights and DFT studies highlight their enhanced reactivity and stability. With their superior performance and practicality, thiazol-2-ylidenes represent a promising class of catalysts for sustainable organic synthesis.