Reversing Enantioselectivity Using Noncovalent Interactions in Asymmetric Dearomatization of β-Naphthols: The Power of 3,3′ Substituents in Chiral Phosphoric Acid Catalysts

The sense of enantioselectivity in asymmetric dearomative amination of β-naphthols is reported to pivotally depend on the 3,3′ substituents on the chiral BINOL–phosphoric acid (CPA) catalysts. The origin of reversal in the sense of stereoinduction from R to S, when the aryl substituent is changed from 3,5-(CF3)2-C6H3 (CPA-1) to 9-anthryl (CPA-2), has been identified as arising due to the change in the pattern of noncovalent interactions (from predominantly C–H···F to C–H···π interactions) in the stereocontrolling transition states.