Chiral Macrocycles for Enantioselective Recognition
Guang Sun, Xue Zhang, Zhe Zheng, Zhiyuan Zhang, Ming Dong, Jonathan L. Sessler, Chunju Li
Abstract
The efficient synthesis of chiral macrocycles with highly enantioselective recognition remains a challenge. We have addressed this issue by synthesizing a pair of chiral macrocycles, namely, R / S -BINOL[2], achieving total isolated yields of up to 62% through a two-step reaction sequence. These macrocycles are readily purified by column chromatography over silica gel without the need for chiral separation, thus streamlining the overall synthesis. R / S -BINOL[2] demonstrated enantioselective recognition toward chiral ammonium salts, with enantioselectivity ( K S / K R ) values reaching up to 13.2, although less favorable separations were seen for other substrates. R / S -BINOL[2] also displays blue circularly polarized luminescence with a | g lum | value of up to 2.2 × 10 –3 . The R / S -BINOL[2] macrocycles of this study are attractive as chiral hosts in that they both display enantioselective guest recognition and benefit from a concise, high-yielding synthesis. As such, they may have a role to play in chiral separations.