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3. Geometric constraints regulated regioselectivity: Pd-catalyzed α-deuteration of pyridines with secondary phosphine oxide.

Author

Zheng, Chenxu, Xue, Jiben, Jiang, Zhi-Jiang, Han, Jiawei, Wang, Jiaxin, Bai, Jian-Fei, Chen, Jia, and Gao, Zhanghua

Subjects
DEUTERATION, QUINOLINE
Abstract

A Pd-catalyzed regioselective H/D exchange at the α-position of pyridines was achieved by employing secondary phosphine oxide as an internal base. The proposed five-membered structure enabled the reaction to overcome its conventional ortho-directing feature, allowing the efficient deuteration of pyridines and quinolines at adjacent sites of N-atoms. [ABSTRACT FROM AUTHOR]

Published
2024
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9. Nickel-catalyzed regioselective hydrogen isotope exchange accelerated by 2-pyridones.

Author

Jiang, Zhi-Jiang, Xu, Si-Han, Su, Yuhang, Hu, Erxun, Han, Jiawei, Bai, Jian-Fei, Tang, Bencan, Chen, Jia, and Gao, Zhanghua

Subjects
HYDROGEN isotopes, ISOTOPE exchange reactions, DEUTERIUM, CARBOXAMIDES, BLOOD substitutes
Abstract

A nickel-catalyzed hydrogen isotope exchange has been developed with acetone-d6 as the deuterium source. The reaction showed an improved kinetic feature of H/D exchange under the assistance of 2-pyridones, efficiently affording regioselective labeled aryl and alkyl carboxamides. [ABSTRACT FROM AUTHOR]

Published
2024
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12. Ortho-Deuteration of Aromatic Aldehydes via a Transient Directing Group-Enabled Pd-Catalyzed Hydrogen Isotope Exchange

Author

Junhua Kong, Yanan Ding, Bencan Tang, Jiang Zhijiang, Hong Cao, Jiayuan Xu, Yan Li, Jia Chen, and Gao Zhanghua

Subjects
inorganic chemicals, chemistry.chemical_compound, Deuterium, Chemistry, Hydrogen isotope, Organic Chemistry, Oxide, Photochemistry, Catalysis
Abstract

A practical and scalable ortho-selective deuteration of aromatic aldehydes was accomplished by Pd-catalyzed hydrogen isotope exchange with deuterium oxide as an inexpensive deuterium source. The use of tert-leucine as a transient directing group facilitates the exchange, affording a wide range of ortho-deuterated aromatic aldehydes with deuterium incorporation up to 97%. The control experiments suggest that the addition of silver trifluoroacetate resists the unexpected reduction of Pd(II), while the theoretical study indicates a rapid reversible concerted metalation-deprotonation process.

Published
2021

19. Palladium-Catalyzed Ligand-Free ortho -Deuteration of Aromatic Carboxylic Acids with D2 O.

Author

Zhang, Ziyin, Jiang, Zhi-Jiang, Cao, Yiwei, Chen, Jia, and Gao, Zhanghua

Subjects
CARBOXYLIC acids, HYDROGEN isotopes, ISOTOPE exchange reactions, BENZOATES, DEUTERIUM oxide, DEUTERIUM, ARAMID fibers
Abstract

A ligand-free, palladium-catalyzed ortho -deuteration of aromatic carboxylic acids was developed using D2 O as the deuterium source. Compared to their meta -substituted analogues, an unusually lower reactivity in para - and ortho -substituted benzoic acids toward hydrogen isotope exchange was observed. Further investigation revealed that the reaction temperature is a critical parameter for the reactivity, and the modified conditions can afford deuterated products with good to excellent deuterium incorporation. [ABSTRACT FROM AUTHOR]

Published
2022
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28. Metal-Free Oxidative Fluorination of Phenols with [18F]Fluoride

Author

Gao, Zhanghua, primary, Lim, Yee Hwee, additional, Tredwell, Matthew, additional, Li, Lei, additional, Verhoog, Stefan, additional, Hopkinson, Matthew, additional, Kaluza, Wojciech, additional, Collier, Thomas Lee, additional, Passchier, Jan, additional, Huiban, Mickael, additional, and Gouverneur, Véronique, additional

Published
2012
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30. A Synthesis of an Ionomycin Calcium Complex

Author

Gao, Zhanghua, primary, Li, Yingfa, additional, Cooksey, John P., additional, Snaddon, Thomas N., additional, Schunk, Stefan, additional, Viseux, Eddy M. E., additional, McAteer, Stephen M., additional, and Kocienski, Philip J., additional

Published
2009
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31. Enhanced Aqueous Suzuki--Miyaura Coupling Allows Site-Specific Polypeptide 18F-Labeling.

Author

Gao, Zhanghua, Gouverneur, Véronique, and Davis, Benjamin G.

Subjects
*SUZUKI reaction, *POLYPEPTIDES, *CHEMICAL reagents, *PROTEINS, *STOICHIOMETRY, *RADIOLABELING, *GUANIDINE, *FLUORINE
Abstract

The excesses of reagents used in protein chemistry are often incompatible with the reduced or even inverse stoichiometries used for efficient radiolabeling. Analysis and screening of aqueous Pd(0) ligand systems has revealed the importance of a guanidine core and the discovery of 1,1-dimethylguanidine as an enhanced ligand for aqueous Suzuki-Miyaura cross-coupling. This novel Pd catalyst system has now allowed the labeling of small molecules, peptides, and proteins with the fluorine-18 prosthetic [18F]4-fluorophenylboronic acid. These findings now enable site-specific protein 18F-labeling under biologically compatible conditions using a metal-triggered reaction. [ABSTRACT FROM AUTHOR]

Published
2013
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33. Copper(II)-Catalyzed Regioselective H/D Exchange Based on Reversible C-H Activation.

Author

Su Y, Jiang ZJ, Han J, Duan L, Bai J, Chen J, and Gao Z

Abstract

Despite the increasing use of copper in C-H functionalizations, the Cu-catalyzed direct deuteration of C-H bonds remains a significant challenge due to its inherent low reactivity in inverse C-H bond reconstruction. In this paper, a novel strategy had been developed to reverse the copper-catalyzed concerted metalation-deprotonation process by inhibiting the unexpected disproportionation of Cu(II) to Cu(III). Picolinic acid was identified as a powerful ligand for facilitating this H/D exchange with D2O as deuterium source, and its inhibition activity was supported by preliminary control experiments and DFT studies., (© 2024 Wiley‐VCH GmbH.)

Published
2024
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34. B(C 6 F 5 ) 3 -Catalyzed Intramolecular Hydroalkoxylation Deuteration Reactions of Unactivated Alkynyl Alcohols.

Author

Tang J, Bai JF, Zheng J, Li S, Jiang ZJ, Chen J, Gao K, and Gao Z

Abstract

Using D 2 O as a deuterium source, a method for the deuteration of intra- and extra-cyclic methylene has been developed for cyclic ethers with moderate yield and excellent deuterium incorporation. This transformation features superb functional group tolerance in a wide range of alkynols. Notably, the critical factor to achieve high deuterium incorporation is determined by the hydrogen isotope exchange reaction of an unstable oxonium ion. This novel methodology provides an efficient and concise synthetic route to a number of valuable deuterated cyclic ethers that are often difficult to prepare with other methods.

Published
2023
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35. A synthesis of an ionomycin calcium complex.

Author

Gao Z, Li Y, Cooksey JP, Snaddon TN, Schunk S, Viseux EM, McAteer SM, and Kocienski PJ

Subjects
Anti-Bacterial Agents chemistry, Catalysis, Cyclization, Gold chemistry, Stereoisomerism, Calcium chemistry, Ionomycin chemistry
Abstract

Caught in the middle: The ionomycin calcium complex (see structure; O red, Ca green) was the target of an approach featuring the efficient asymmetric synthesis of an allene by a copper(I)-mediated anti-selective S(N)2' reaction, a highly stereoselective gold(III)-catalyzed cycloisomerization of an alpha-hydroxyallene, and a Rh-catalyzed rearrangement of an alpha-diazo-beta-hydroxyketone.

Published
2009
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