1
|
Gu G, Xu Z, Wen L, Liang J, Wang C, Wan X, Zhao Y. Chirality Sensing of N-Heterocycles via 19F NMR. JACS AU 2023; 3:1348-1357. [PMID: 37234104 PMCID: PMC10206601 DOI: 10.1021/jacsau.2c00661] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 02/20/2023] [Accepted: 04/20/2023] [Indexed: 05/27/2023]
Abstract
Methods to rapidly detect and differentiate chiral N-heterocyclic compounds become increasingly important owing to the widespread application of N-heterocycles in drug discovery and materials science. We herein report a 19F NMR-based chemosensing approach for the prompt enantioanalysis of various N-heterocycles, where the dynamic binding between the analytes and a chiral 19F-labeled palladium probe create characteristic 19F NMR signals assignable to each enantiomer. The open binding site of the probe allows the effective recognition of bulky analytes that are otherwise difficult to detect. The chirality center distal to the binding site is found sufficient for the probe to discriminate the stereoconfiguration of the analyte. The utility of the method in the screening of reaction conditions for the asymmetric synthesis of lansoprazole is demonstrated.
Collapse
Affiliation(s)
- Guangxing Gu
- Key
Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic
Chemistry, University of Chinese Academy
of Sciences, Chinese Academy of Sciences, 345 Ling-Ling Road, Shanghai 200032, China
| | - Zhenchuang Xu
- Key
Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic
Chemistry, University of Chinese Academy
of Sciences, Chinese Academy of Sciences, 345 Ling-Ling Road, Shanghai 200032, China
| | - Lixian Wen
- Key
Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic
Chemistry, University of Chinese Academy
of Sciences, Chinese Academy of Sciences, 345 Ling-Ling Road, Shanghai 200032, China
| | - Jinhua Liang
- Key
Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic
Chemistry, University of Chinese Academy
of Sciences, Chinese Academy of Sciences, 345 Ling-Ling Road, Shanghai 200032, China
| | - Chenyang Wang
- Key
Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic
Chemistry, University of Chinese Academy
of Sciences, Chinese Academy of Sciences, 345 Ling-Ling Road, Shanghai 200032, China
| | - Xiaolong Wan
- Shanghai
Institute of Organic Chemistry, Chinese
Academy of Sciences, 345 Ling-Ling Road, Shanghai 200032, China
| | - Yanchuan Zhao
- Key
Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic
Chemistry, University of Chinese Academy
of Sciences, Chinese Academy of Sciences, 345 Ling-Ling Road, Shanghai 200032, China
- Key
Laboratory of Energy Regulation Materials, Shanghai Institute of Organic
Chemistry, Chinese Academy of Sciences, 345 Ling-Ling Road, Shanghai 200032, China
| |
Collapse
|
2
|
Sun W, Tikhonov DS, Singh H, Steber AL, Pérez C, Schnell M. Inducing transient enantiomeric excess in a molecular quantum racemic mixture with microwave fields. Nat Commun 2023; 14:934. [PMID: 36807276 PMCID: PMC9941128 DOI: 10.1038/s41467-023-36653-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 02/10/2023] [Indexed: 02/22/2023] Open
Abstract
Chiral molecules with low enantiomer interconversion barriers racemize even at cryogenic temperatures due to quantum tunneling, forming a racemic mixture that is impossible to separate using conventional chemical methods. Here we both experimentally and theoretically demonstrate a method to create and probe a state-specific enantiomeric enrichment for such molecular systems. The coherent, non-linear, and resonant approach is based on a microwave six-wave mixing scheme and consists of five phase-controlled microwave pulses. The first three pulses induce a chiral wavepacket in a chosen rotational state, while the consecutive two pulses induce a polarization for a particular rotational transition (listen transition) with a magnitude proportional to the enantiomeric excess created. The experiments are performed with the transiently chiral molecule benzyl alcohol, where a chiral molecular response was successfully obtained. This signal demonstrates that enantiomeric excess can be induced in a quantum racemic mixture of a transiently chiral molecule using the developed microwave six-wave mixing scheme, which is an important step towards controlling non-rigid chiral molecular systems.
Collapse
Affiliation(s)
- Wenhao Sun
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
- Institute of Physical Chemistry, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Str. 1, 24118, Kiel, Germany
| | - Denis S Tikhonov
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
- Institute of Physical Chemistry, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Str. 1, 24118, Kiel, Germany
| | - Himanshi Singh
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
- Institute of Physical Chemistry, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Str. 1, 24118, Kiel, Germany
| | - Amanda L Steber
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
- Institute of Physical Chemistry, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Str. 1, 24118, Kiel, Germany
- Departamento de Química Física y Química Inorgánica, Facultad de Ciencias-I.U. CINQUIMA, Universidad de Valladolid, E-47011, Valladolid, Spain
| | - Cristóbal Pérez
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany
- Institute of Physical Chemistry, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Str. 1, 24118, Kiel, Germany
- Departamento de Química Física y Química Inorgánica, Facultad de Ciencias-I.U. CINQUIMA, Universidad de Valladolid, E-47011, Valladolid, Spain
| | - Melanie Schnell
- Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany.
- Institute of Physical Chemistry, Christian-Albrechts-Universität zu Kiel, Max-Eyth-Str. 1, 24118, Kiel, Germany.
| |
Collapse
|
3
|
Construction and Demonstration of a 6–18 GHz Microwave Three-Wave Mixing Experiment Using Multiple Synchronized Arbitrary Waveform Generators. Symmetry (Basel) 2022. [DOI: 10.3390/sym14050848] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
This manuscript details the construction and demonstration of the first known microwave three-wave mixing (M3WM) experiment utilizing multiple arbitrary waveform generators (AWGs) completely operable in the 6–18 GHz frequency range for use in chirality determination and quantification. Many M3WM techniques, which involve two orthogonal, subsequent Rabi π/2 and π microwave pulses, suffer from flexibility in pulse types and timings as well as frequency due to most instruments only using one, one-channel AWG and the M3WM probability decreasing with an increasing quantum number, J. In this work, we presented an M3WM instrument that allows that flexibility by introducing multiple, synchronized AWGs and adheres to the high probability transition loop pathways in carvone. The functionality and reliability of the instrument were demonstrated using a series of experiments and mixtures of the R and S enantiomers and determined to be of similar accuracy to other reported M3WM setups with the additional benefit of flexibility in pulsing schemes.
Collapse
|