Tunable Diastereoselective Desymmetrization of Cyclohexadienones Triggered by Copper-Catalyzed Three-Component Coupling Reaction

Catalytic
tandem diastereoselective desymmetrization of cyclohexadienone-containing
1,6-enynes has been achieved through copper-catalyzed [3 + 2]-cycloaddition
followed by ketenimine formation and subsequent intramolecular conjugate
addition. The cascade reaction provides cis-hydrobenzofurans
in good yields with excellent diastereoselectivity. The exo- or endo-selectivity of bicyclic scaffolds depends
on the selection of the base in the reaction. In addition, N-tethered bicyclic products further transformed into tricyclic
compounds via intramolecular Michael addition.