Room‐Temperature Hydration of Alkynes Catalyzed by Different Carbene Gold Complexes and their Precursors

The room‐temperature hydration of alkynes catalyzed by NHC‐gold(I) (NHC=N‐heterocyclic carbene), NAC‐gold(I) (NAC=nitrogen acyclic carbene), and isocyanide gold(I) complexes was investigated carefully in the presence of different weakly coordinating anions. NHC(IPr)‐AuCl/KB(C 6 F 5 ) 4 (NHC(IPr)=1,3‐bis(2,6‐diisopropylphenyl)imidazol‐2‐ylidene) was found to be the most active catalyst at room temperature, and the room‐temperature hydration of different alkynes could be completed in 7 h using only 0.5 mol % NHC(IPr)‐AuCl/KB(C 6 F 5 ) 4 . It was further demonstrated that the catalyst system could be simply reused at least six times without a noticeable loss of catalytic activity.