Gold-Catalyzed Dimerization of Diarylalkynes: Direct Access to Azulenes
作者:Vanessa Claus、Michael Schukin、Siegfried Harrer、Matthias Rudolph、Frank Rominger、Abdullah M. Asiri、Jin Xie、A. Stephen K. Hashmi
DOI:10.1002/anie.201805918
日期:2018.9.24
We have developed a simple gold‐catalyzed procedure for the synthesis of substituted and modifiable azulenes. The azulenes are formed either by the dimerization of push–pull diarylalkynes bearing a fluorine atom in ortho or para position or by the dimerization of a symmetric electron‐rich diarylalkyne. In the presence of a cationic gold catalyst, the two alkynes can form a highly reactive vinyl cation
degrees C under an aerobicconditions smoothly undergoes homo-coupling to give the corresponding symmetrical 1,3-butadiynes in 70-99% yields. In addition, (arylethynyl)trimethylsilanes are found to couple with aryl triflates and chlorides in the presence of Cu(I)/Pd(0) (10 mol %/5 or 10 mol %) cocatalyst system to give the corresponding diarylethynes in 49-99% yields. The cross-coupling reaction is