Detection and Chiral Recognition of α‐Hydroxyl Acid through 1H and CEST NMR Spectroscopy Using a Ytterbium Macrocyclic Complex. Issue 50 (30th October 2019)

• Record Type: Journal Article
• Authors: He, Haonan; Zhao, Kelu; Xiao, Long; Zhang, Yi; Cheng, Yi; Wan, Sikang; Chen, Shizhen; Zhang, Lei; Zhou, Xin; Liu, Kai; Zhang, Hongjie
• Is Part Of: Angewandte Chemie international edition. Volume 58:Issue 50(2019)
• Page Start: 18286
• Page End: 18289
• Publication Date: 2019-10-30
• Subjects: alpha hydroxyl acids -- CEST -- chiral recognition -- NMR spectroscopy -- Yb complexes; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201912072
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: Chiral α‐hydroxyl acids are of great importance in chemical synthesis. Current methods for recognizing their chirality by 1 H NMR are limited by their small chemical shift differences and intrinsic solubility problem in organic solvents. Herein, we developed three YbDO3A(ala)3 derivatives to recognize four different commercially available chiral α‐hydroxyl acids in aqueous solution through 1 H NMR and chemical exchange saturation transfer (CEST) spectroscopy. The shift difference between chiral α‐hydroxyl acid observed by proton and CEST NMR ranged from 15–40 and 20–40 ppm, respectively. Our work demonstrates for first time, that even one chiral center on the side‐arm chain of cyclen could set the stage for rotation of the other two non‐chiral side chains into a preferred position. This is ascribed to the lower energy state of the structure. The results show that chiral YbDO3A‐like complexes can be used to discriminate chiral α‐hydroxyl acids with a distinct signal difference. Abstract : Chiral and CEST : Three YbDO3A(ala)3 derivatives display the ability to act as a chiral recognition reagent for alpha hydroxyl acids based on proton and chemical exchange saturation transfer (CEST) NMR spectroscopy in an aqueous environment. The sensitivity ranged from 15 to 40 ppm.