Tailoring the Performance of 19F-Labeled Probes via Dynamic Covalent Chemistry for Improved Chiral Discrimination.

This work presents a novel strategy for postmodifying probes using dynamic covalent chemistry. Leveraging reversible interactions between boronic acid and diols, we obtained a panel of 19F-labeled probes with distinct resolving abilities. This approach enables rapid identification of probes with satisfactory performance, streamlining synthesis, and enhancing efficiency in chiral analysis. Our findings demonstrate an exceptional ability to differentiate compounds with distal chirality and challenging aliphatic amines. The postmodified probes also exhibit accuracy and reliability in determining enantiomeric excess, promising advancements in enantio-analysis techniques and chiral discrimination.

Detection and Identification of Nitrile Compounds via Recognition-Enabled Chromatographic 19F NMR.

The surge in applications of nitrile compounds across diverse fields, such as pharmaceuticals, agrochemicals, dyes, and functional materials, necessitates the development of rapid and efficient detection and identification methods. In this study, we introduce a chemosensing strategy employing a novel 19F-labeled probe, facilitating swift and accurate analysis of a broad spectrum of nitrile-containing analytes. This approach leverages the reversible interaction between the 19F-labeled probe and the analytes to produce chromatogram-like outputs, ensuring the precise identification of various pharmaceuticals and pesticides within complex matrices. Additionally, this dynamic system offers a versatile platform to investigate through-space 19F-19F interactions, showcasing its potential for future applications in mechanistic studies.

Chiral Discrimination of Acyclic Secondary Amines by 19F NMR.

Chiral aliphatic amine compounds exhibit a range of physiological activities, making them highly sought-after in the pharmaceutical industry and biological research. One notable obstacle in studying these compounds stems from the pronounced steric hindrance surrounding the nitrogen atom. This characteristic often leads to a weak affinity of acyclic secondary amines for molecular probes, making their chiral discrimination intricate. In response to this challenge, our research has unveiled a novel 19F-labeled probe adept at recognizing and distinguishing between enantiomers of these acyclic secondary amines. By strategically incorporating a single fluorine atom as the 19F label, we have managed to diminish the steric hindrance at the binding site. This alteration bolsters the probe's affinity toward bulkier analytes. As a testament to its effectiveness, we have successfully employed our probe in the chiral analysis of relevant pharmaceuticals, accurately determining their enantiocomposition.

Synthesis of Diaryl Ethers via Hypervalent Iodine-Mediated C-H Functionalization.

A hypervalent iodine-reagent-based C-H functionalization strategy was utilized to synthesize diaryl ethers. This method directly transforms various arenes into their corresponding diaryliodonium salts, followed by a C-O coupling reaction to produce structurally diverse diaryl ethers. The efficacy of this approach in the late-stage structural modifications of complex molecules was demonstrated.

A high-performance chiral 19F-labeled probe with an increased structural twisting.

We developed a new strategy to enhance the chiral discrimination capability of 19F-labeled probes by tuning the torsion angle of the probe's backbone, allowing for the resolution of challenging analytes. Its versatility is demonstrated through the superior performance and the wide analyte scope.

Chiral Discrimination of Nitrile Compounds Using a 19F-Labeled Palladium Probe.

This study presents a 19F-labeled cyclopalladium probe for the rapid discrimination of chiral nitriles in pharmaceuticals, natural products, and agrochemicals. The probe binds reversibly to chiral nitriles, generating distinct 19F nuclear magnetic resonance signals for each enantiomer and enabling quick determination of enantiocomposition. The method allows for simultaneous detection of seven pairs of enantiomeric nitriles and application in assessing the enantiomeric excess of an asymmetric C-H cyanation reaction.

Chirality Sensing of N-Heterocycles via 19F NMR.

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.