Multi-step chirality transfer and racemization kinetics of pillar [5]arenes by tuning the halogen substituents on the rims†

Abstract

Halogen-substituted pillar[5]arenes exhibited hindered hydroquinone subunit flipping, enabling enantioseparation. An enantiopure conformer showed a dissymmetric factor of 0.012 and an enantioselective binding ratio exceeding 1.92. Complexation with l-serine induced an enantiopreference in pillar[5]arene, which persisted for a certain period after chiral inducer removal and reversed upon the addition of d-serine. This induced enantiopreference was subsequently transferred to a chromophore guest, achieving a multi-step chiral transfer process. This approach offers a potential alternative to traditional chiral HPLC methods, enabling the manipulation of chiral recognition and transfer through chiral inducers.