Gold‐Catalyzed Conversion of Aryl‐ and Alkyl‐Substituted 1‐(<i>o</i>‐Aminophenyl)‐2‐propyn‐1‐ones to the Corresponding 2‐Substituted 4‐Quinolones

Abstract

Abstract 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 Au I species. In particular PPh 3 AuNTf 2 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.