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53. Radical deuteration

Author

Li, Nian, primary, Li, Yantao, additional, Wu, Xiaopeng, additional, Zhu, Chengjian, additional, and Xie, Jin, additional

Published
2022
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63. Highly selective single and multiple deuteration of unactivated C(sp3)-H bonds.

Author

Li, Nian, Li, Jinhang, Qin, Mingzhe, Li, Jiajun, Han, Jie, Zhu, Chengjian, Li, Weipeng, and Xie, Jin

Subjects
DEUTERATION, ABSTRACTION reactions, MATERIALS science, PHARMACEUTICAL chemistry, BONDS (Finance)
Abstract

Selective deuteration of unactivated C(sp3)-H bonds is a highly attractive but challenging subject of research in pharmaceutical chemistry, material science and synthetic chemistry. Reported herein is a practical, highly selective and economical efficient hydrogen/deuterium (H/D) exchange of unactivated C(sp3)-H bonds by synergistic photocatalysis and hydrogen atom transfer (HAT) catalysis. With the easily prepared PMP-substituted amides as nitrogen-centered radical precursors, a wide range of structurally diverse amides can undergo predictable radical H/D exchange smoothly with inexpensive D2O as the sole deuterium source, giving rise to the distal tertiary, secondary and primary C(sp3)-H bonds selectively deuterated products in yields of up to 99% and excellent D-incorporations. In addition to precise monodeuteration, this strategy can also achieve multideuteration of the substrates contain more than one remote C(sp3)-H bond, which opens a method to address multi-functionalization of distal unactivated C(sp3)–H bonds. Deuteration of unactivated C(sp3)̵̵̵̵̵̵̵̵–H bonds is a simple route to deuterated compounds, of use in pharmaceutical chemistry, material science, and synthetic chemistry. Here, the authors describe a hydrogen/deuterium (H/D) exchange of remote unactivated C(sp3)̵̵̵̵̵̵̵̵–H bonds via photocatalysis, proceeding through hydrogen atom transfer. [ABSTRACT FROM AUTHOR]

Published
2022
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66. Decarboxylative tandem C-N coupling with nitroarenes via SH2 mechanism.

Author

Wang, Shuaishuai, Li, Tingrui, Gu, Chengyihan, Han, Jie, Zhao, Chuan-Gang, Zhu, Chengjian, Tan, Hairen, and Xie, Jin

Subjects
TERTIARY amines, AROMATIC amines, NITROAROMATIC compounds, ORGANIC chemistry, ORGANIC compounds, PHARMACEUTICAL chemistry
Abstract

Aromatic tertiary amines are one of the most important classes of organic compounds in organic chemistry and drug discovery. It is difficult to efficiently construct tertiary amines from primary amines via classical nucleophilic substitution due to consecutive overalkylation. In this paper, we have developed a radical tandem C-N coupling strategy to efficiently construct aromatic tertiary amines from commercially available carboxylic acids and nitroarenes. A variety of aromatic tertiary amines can be furnished in good yields (up to 98%) with excellent functional group compatibility under mild reaction conditions. The use of two different carboxylic acids also allows for the concise synthesis of nonsymmetric aromatic tertiary amines in satisfactory yields. Mechanistic studies suggest the intermediacy of the arylamine–(TPP)Fe(III) species and might provide a possible evidence for an SH2 (bimolecular homolytic substitution) pathway in the critical C-N bond formation step. Aromatic tertiary amines are versatile building blocks in organic synthesis. In this article, the authors report on an iron-catalysed reaction for the decarboxylative C-N coupling from carboxylic acids and nitroarenes, leading to non-symmetric tertiary aromatic amines. [ABSTRACT FROM AUTHOR]

Published
2022
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86. Direct Deoxygenative Intramolecular Acylation of Biarylcarboxylic Acids.

Author

Li, Yantao, Xu, Wentao, Zhu, Chengjian, and Xie, Jin

Abstract

A photocatalyzed intramolecular cyclization is developed for the synthesis of fluorenones. In this photoredox reaction, triphenylphosphine is used as an inexpensive and effective deoxygenative reagent for biarylcarboxylic acids to give acyl radicals, which quickly undergo intramolecular radical cyclization. Reactions in the presence of air and continuous flow photoredox technology demonstrate the generality and practicality of this process. [ABSTRACT FROM AUTHOR]

Published
2021
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87. Tandem dual C(sp3)-H/C(sp2)-H functionalization: a radical cyclization of 2-isocyanobiphenyl with ether to 6-alkylated phenanthridine

Author

ChangDuo Pan, Zhu ChengJian, and Jie Han

Subjects
chemistry.chemical_compound, Cascade reaction, Phenanthridine, Chemistry, Stereochemistry, Kinetic isotope effect, Phenyl group, Ether, General Chemistry, Alkylation, Cleavage (embryo), Radical cyclization
Abstract

A simple and efficient radical coupling of 2-isocyanobiphenyl with ethers was developed, providing a variety of 6-alkylated phenanthridines. Both cyclic and acyclic ethers are suitable substrates for this transformation, which comprised the functionalization of two C-H bonds: the sp3 C-H of ether and sp2 C-H of phenyl group. The kinetic isotope effect (KIE) revealed that the cleavage of sp3 C-H bond would be involved in the rate-determining step.

Published
2014

88. Exploration of C–H Transformations of Aldehyde Hydrazones: Radical Strategies and Beyond

Author

Xu, Pan, Li, Weipeng, Xie, Jin, and Zhu, Chengjian

Abstract

The chemistry of hydrazones has gained great momentum due to their involvement throughout the evolution of organic synthesis. Herein, we discuss the tremendous developments in both the methodology and application of hydrazones. Hydrazones can be recognized not only as synthetic equivalents to aldehydes and ketones but also as versatile synthetic building blocks. Consequently, they can participate in a range of practical synthetic transformations. Furthermore, hydrazone derivatives display a broad array of biological activities and have been widely applied as pharmaceuticals. Owing to the weak directing group effect of simple aldehydes and ketones in C–H bond functionalizations, the C–H bond functionalizations of hydrazones that have been developed in the past five years represent a significant step forward. These novel transformations open a new door to a broader library of functionalized and complex small molecules. Moreover, a wide range of biologically important N-heterocycles (dihydropyrazoles, pyrazoles, indazoles, cinnolines, etc.) can be efficiently synthesized in an atom- and step-economical manner through single, double, or triple C–H bond functionalizations of hydrazones. Both radical C–H functionalizations and transition-metal-catalyzed directing-group strategies have enhanced the synthetic utility of hydrazones in the chemical community because these strategies solve the long-standing challenge of C–H functionalizations adjacent to aldehydes and ketones.

Published
2024
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89. Domino-Fluorination–Protodefluorination Enables Decarboxylative Cross-Coupling of α-Oxocarboxylic Acids with Styrene via Photoredox Catalysis

Author

Zhang, Muliang, Xi, Junwei, Ruzi, Rehanguli, Li, Nan, Wu, Zhongkai, Li, Weipeng, and Zhu, Chengjian

Abstract

Domino-fluorination–protodefluorination decarboxylative cross-coupling of α-keto acids with styrene has been developed via photoredox catalysis. The critical part of this strategy is the formation of the carbon–fluorine (C–F) bond by the capture of a carbon-centered radical intermediate, which will overcome side reactions during the styrene radical functionalization process. Experimental studies have provided evidence indicating a domino-fluorination–protodefluorination pathway with α-keto acid initiating the photoredox cycle. The present catalytic protocol also affords a novel approach for the construction of α,β-unsaturated ketones under mild conditions.

Published
2024
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