Macrocyclic compounds as chiral solvating agents for phosphinic, phosphonic, and phosphoric acids
摘要:
Novel macrocyclic compounds, synthesized and used as chiral solvating agents for phosphinic, phosphonic, and phosphoric acids, are reported in this article. NMR (H-1 NMR and/or P-31 NMR) studies demonstrate that these acids have large nonequivalent chemical shifts in the presence of these macrocyclic compounds. Quantitative analyses of a series of the selected phosphinic acids with different enantiomeric purities show the high accuracy of this method. (c) 2007 Elsevier Ltd. All rights reserved.
The novel macrocyclic compounds 1-8 and acyclic compound 9 were designed and synthesized. (1)H NMR studies demonstrated that 1 and 2 were the best chiral solvating agents, and are effective for the determination of the enantiomeric excess of a wide range of alpha-chiral carboxylic acids. Large non-equivalent chemical shifts (up to 411.2 Hz) can be achieved in the presence of 1 and 2. Quantitative analyses of a series of mandelic acids with different enantiomeric purities demonstrate that 1 and 2 are excellent chiral solvating agents for carboxylic acids. (C) 2008 Elsevier Ltd. All Fights reserved.