Franta, Maximilian and Pattanaik, Aryaman and Silva, Wagner and Motiram-Corral, Kumar and Rehbein, Julia and Gschwind, Ruth M. (2025) The Elusive Ternary Intermediates of Chiral Phosphoric Acids in Ion Pair Catalysis-Structures, Conformations, and Aggregation. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 147 (3). pp. 2549-2558. ISSN 0002-7863, 1520-5126
Full text not available from this repository. (Request a copy)Abstract
In ion-pair catalysis, the last intermediate structures prior to the stereoselective transition states are of special importance for predictive models due to the high isomerization barrier between E- and Z-substrate double bonds connecting ground and transition state energies. However, in prior experimental investigations of chiral phosphoric acids (CPA) solely the early intermediates could be investigated while the key intermediate remained elusive. In this study, the first experimental structural and conformational insights into ternary complexes with CPAs are presented using a special combination of low temperature and relaxation optimized 15N HSQC-NOESY NMR spectroscopy to enhance sensitivity. Combined NMR investigations and theoretical calculations revealed three conformers of the ternary complex, of which one also closely resembles the previously calculated transition states. In addition, a 2:1:1 ternary complex as well as an unprecedent [3:3] dimeric species consisting of two ternary complexes was revealed. Given the importance of the ground state energies for the transition state interpretation in ion pair catalysis we believe that the presented experimental insight into the structural and conformational variety of the ternary complexes is a key to the future development of predictive models in ion pair catalysis.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ASYMMETRIC TRANSFER HYDROGENATION; BRONSTED ACID; NMR DETECTION; N-ACYL; ENANTIOSELECTIVITY; BONDS; ORGANOCATALYSIS; MECHANISM; 3,3'-SUBSTITUENTS; REDUCTION; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Organische Chemie > Arbeitskreis Prof. Dr. Ruth Gschwind |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 16 Jun 2026 08:14 |
| Last Modified: | 16 Jun 2026 08:14 |
| URI: | https://pred.uni-regensburg.de/id/eprint/65998 |
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