Gold-catalyzed Bicyclization of Diaryl Alkynes: Synthesis of Polycyclic Fused Indole and Spirooxindole Derivatives
†College of Chemistry, Chemical Engineering and Materials Science,Soochow University,Suzhou215123,China
‡School of Pharmaceutical Sciences,Sun Yat-Sen University,Guangzhou510006,China
Org. Lett.,2018,20(9), 2733--2736
An unprecedented gold-catalyzed bicyclization reaction of diaryl alkynes has been developed for the synthesis of indoles in good to high yields. Mechanistically, this alkyne bifunctionalization transformation was terminated by a stepwise formal X–H insertion reaction to furnish the corresponding polycyclic-frameworks with structural diversity, and the key intermediate 3H-indole was isolated and characterized for the first time. In addition, further transformation of these generated tetracyclic-indoles with PCC as the oxidant provided straightforward access to the spirooxindoles in high yields.