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

摘要

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(C6F5)(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(C6F5)(4). It was further demonstrated that the catalyst system could be simply reused at least six times without a noticeable loss of catalytic activity.