Palladium-Catalyzed Cascade 5- exo-dig Annulation and Amination for Assembly of Amino-Functionalized Trisubstituted Furans

A novel route for the preparation of trisubstituted furans with an amino functional group is presented as a palladium-catalyzed cascade 5-exo-dig annulation/amination reaction of α-alkynyl-α,β-enones with N-hydroxybenzamides. The reaction proceeds through a cascade sequence of intramolecular 5-exo-dig annulation, amination, Lossen rearrangement, and decarboxylation, forming two new C-X (X = O, N) bonds in a one-step transformation. This cascade protocol features a wide substrate range and outstanding functional group compatibility and allows an efficient large-scale synthesis and downstream transformations of the target products.