Perfluorinated Aryls in the Design of Chiral Brønsted Acid Catalysts: Catalysis of Enantioselective [4 + 2] Cycloadditions and Ene Reactions of Imines with Alkenes by Chiral Mono-Phosphoric Acids with Perfluoroaryls
aryl-incorporating chiral monophosphoric acids were used for highly stereoselective reactions of N-acyl and N-acyloxy aldimines with styrenes. Their electronic and steric profiles were established in comparison with those of phenyl, binaphthyl, and partially fluorinated aryls. The [4 + 2] cycloadditionreactions of N-benzoyl aldimines with alkenes proceeded with excellent diastereo- and enantioselectivities in the