Novel approach with amide-tethered H-bond donor NHC ligands enabled Au(I)-catalysis via H-bonding. The plain NHC-Au(I)-Cl complex catalysed conversions of terminal N-propynamides to oxazolines, and enyne cycloisomerization with an acid additive,...

Gold‐catalyzed cyclization of alkyl‐ or aryl‐substituted 1‐(o‐aminophenyl)‐2‐propyn‐1‐ones to the corresponding 2‐substituted 4‐quinolones was studied with various gold salts and complexes. Screening of the different catalysts showed highest performance with cationic AuI species. In particular PPh3AuNTf2 complex was the most efficient catalyst. Relative to classic quinolone synthesis that requires harsh cyclocondensation conditions, the current method offers a mild and atom‐economic alternative. Mechanistically, DFT studies at TPSS‐D3/def2‐TZVP level suggest that gold operates in an alkynophilic manner rather than through conjugative carbonyl activation.