Design of Chiral Bis-phosphoric Acid Catalyst Derived from (<i>R</i>)-3,3′-Di(2-hydroxy-3-arylphenyl)binaphthol: Catalytic Enantioselective Diels–Alder Reaction of α,β-Unsaturated Aldehydes with Amidodienes
Chiral bis-phosphoric acid 1 was designed to identify a new class of structural features in chiral Brønsted acid catalysts. X-ray diffraction analysis revealed the single atropisomer 1, bearing S axial chirality at 3,3'-biaryl substituents on (R)-binaphthyl and intramolecular hydrogen bonding between the two phosphoric acid moieties. The newly designed bis-phosphoric acid 1 was evaluated in the Diels-Alder