Bispentiptycenyl‐N‐Heterocyclic Carbene (NHC) Gold Complexes: Highly Active Catalysts for the Room Temperature Hydration of Alkynes

The virtually quantitative, room temperature hydration of various terminal and internal alkynes in methanol/water requires between 0.01–0.05 mol% of [AuCl(NHC)] activated with 1.5 equiv. of silver triflate and 45 equiv. of triflic acid (both relative to gold complex) with ton of up to 300.000. Iptycenyl‐substituted NHC ligands play the key role and the most efficient NHC ligand is characterized by a hemispherical shape formed by two N‐pentiptycenyl substituents.