Chiral Bronsted Acid-Catalyzed Asymmetric 1,4-Addition of Benzofuran-Derived Azadienes with 3-Substituted indoles

A chiral phosphoric acid-catalyzed asymmetric 1,4-addition of benzofuran-derived azadienes with 3-substituted indoles has been established, which offered enantioenriched tri(hetero)arylmethane products in generally good yields (up to 98 %) and high enantioselectivities (up to 99 : 1 er). This reaction has not only realized the application of chiral phosphoric acid as a competent catalyst in the asymmetric transformations of benzofuran-derived azadienes, but also has accomplished the task of developing chiral Bronsted acid-catalyzed asymmetric 1,4-additions of benzofuran-derived azadienes, which will enrich the research contents of chiral phosphoric acid catalysis and the chemistry of benzofuran-derived azadienes.