Stereoselective α-indolylation of enals via an organocatalytic formal cross-coupling with indoles

We report a novel organocatalytic one-pot cascade bromination–Michael-type Friedel–Crafts alkylation dearomatization–nucleophilic rearrangement aromatization cascade process for the direct α-indolylation of unfunctionalized enals from readily available indoles with good yields and high E selectivity. The simplicity and practicality of its high efficiency for formation of a new C(sp2)–C(sp2) bond constitute the most attractive advantage of this reaction.