Synthesis and Catalytic Activity of Coumarin- and Chrysin-Tethered Triazolylidene Gold(I) Complexes

A series sterically?encumbered coumarin? (1) and chrysin?functionalized triazolium salts (2,3) have been synthesized stepwise via copper catalyzed alkyne?azide cycloaddition and N?alkylation procedures. Their one?pot deprotonation with KHMDS in presence of AuCl(SMe2) allowed for the preparation of the corresponding triazolylidene gold(I) complexes (4?6) in high yields (75?92?%). All new compounds were fully characterized by means of 1H and 13C NMR spectroscopy, FT?IR, elemental analyses and in the case of triazole F, triazolium 1 and the gold complex 4, by single?crystal X?ray diffraction. The new triazolylidene gold complexes (4?6) were tested as precatalysts in the synthesis of indole derivatives via an intramolecular hydroamination reaction of several readily available anilines.