Gold(I)-Catalyzed\nSynthesis of 2,2′-Biindoles\nvia One-Pot Double Cycloisomerization Strategy

The first systematic, concise and target-directed gold(I)-catalyzed\nsynthesis of a family of 2,2′-biindoles containing different\nsubstitution patterns is described. The developed protocol involves\nthe synthesis of 1,3-diyne-anilines followed by a one-pot gold(I)-catalyzed\ndouble cycloisomerization, giving rise to an efficient, broad and\ngeneral protocol to get different 2,2′-biindoles under mild\nreaction conditions. Due to the methodological restriction of present\nmethods for accessing this class of compounds, herein we present our\nsynthetic proposal which allowed the preparation of several examples\nof 2,2′-biindoles. Their functionalization-guided us to the\ndiscovery that the chemical stability, is substitution structure-dependent.