| Gold catalysis is considered as a promising strategy in organic synthesis due to the fact that numerous new discoveries have been reported over past decades. Gold complex is capable of activating acetylenic bonds with its unique π-acidity, facilitating different types of reactions.Meanwhile, cascade reactions are environmentally benign transformations with high atom economy and low waste generation. Hence the development of gold catalyzed cascade reactions would provide efficient and straightforward synthesis of polycyclic compounds from easily accessible starting material, which will be greatly interesting in both theoretical studies and synthetic applications.An unprecedented gold-catalyzed multiple cascade reaction between 2-alkynyl arylazides and alkynols has been developed, allowing for the step-economical synthesis of pyrroloindolone derivatives with a wide range of structural diversity. In this reaction, the gold complex participates in triple catalysis in tandem fashion.Moreover, the efficient chirality transfer from optically pure alkynol substrates enables facile access to chiral pyrroloindolone derivatives with two stereogenic centers, including a quaternary one, with excellent levels of optical purity.We have discovered an unprecedented gold-catalyzed synthetic method for the direct assembly of aryl-annulated[a]carbazoles from 2-alkynyl arylazides and alkynes. The reaction was proposed to proceed via a sequential cyclopropenation and intramolecular metal carbene/arene Friedel-Crafts-type reaction, respectively mediated by two gold carbene intermediates. The potential applications of the method in the preparation of benzo[a]carbazole-containing compounds that have found great applications in material science have also been elucidated.The hybrid Au(I)/Br(?)nsted acid binary catalyst system enables enynes to participate in an asymmetric relay catalytic cascade intramolecular hydrosiloxylation/asymmetric hetero-Diels-Alder reaction with fluorenyl glyoxylate. |
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