Multiselective Diels-Alder Reaction of alpha-Arylacroleins Catalyzed by Boron Tribromide-Assisted Chiral Phosphoric Acids

A multiselective Diels-Alder (DA) reaction of alpha-arylacroleins with cyclopentadiene using BBr3-assisted chiral BINOL-derived phosphoric acid catalysts has been developed. This unusual exo- and enantioselective DA reaction can be multicontrolled by the chiral cavity of the in situ-formed acid-base cooperative catalysts, in particular, suppressing the competitive hetero Diels-Alder (HDA) reaction effectively.