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19 results on '"He, Xian-Chen"'

16. Mechanochemical Synthesis of 2‐Arylquinoxalines and 3‐Arylquinoxalin‐2(1H)‐ones via Aryldiazonium Salts.

Author

Liu, Fu, Chen, Li‐Ning, Chen, Ai‐Min, Ye, Zhi‐Peng, Wang, Zhi‐Wei, Liu, Zhi‐Lin, He, Xian‐Chen, Li, Shu‐Hui, and Xia, Peng‐Ju

Subjects
ARYL radicals, CHARGE exchange, BALL mills, SALTS
Abstract

A green synthesis strategy of 2‐arylquinoxalines and 3‐arylquinoxalin‐2(1H)‐ones via ball milling, which could avoid copious solvent waste, was accomplished in this work. Aryl radicals were produced from aryldiazonium salts by using a solvent‐free or catalyst‐free single electron transfer process induced by mechanical force, affording a series of 2‐arylquinoxalines and 3‐arylquinoxalin‐2(1H)‐ones with 28%–85 yield. [ABSTRACT FROM AUTHOR]

Published
2022
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17. Visible Light-Induced, Nickel-Catalyzed Late-Stage 4-Alkylation of Hantzsch Esters with Alkyl Bromide

Author

Liu, Yan-Ling, He, Xian-Chen, Gao, Jie, Li, Ke-Rong, Chen, Kai, Xiang, Hao-Yue, and Yang, Hua

Abstract

Herein, visible light-induced, nickel-catalyzed direct functionalization of the Hantzsch esters (HEs) with readily accessible alkyl bromides has been successfully achieved by taking advantage of HE as the reductant and substrate through an aromatization-dearomatization process. In this strategy, the single electron reduction of alkyl bromides by reactive Ni(I) species is essential for the success of this late-stage transformation. A wide range of 4-alkyl-1,4-dihydropyridines were rapidly assembled in moderate to good yields under mild conditions, rendering this photoinduced approach attractive for synthetic and medicinal chemistry.

Published
2024
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18. Photoredox/Nickel Dual Catalysis-Enabled Aryl Formylation with 2,2-Dimethoxy- N , N -dimethylethan-1-amine as CO Source.

Author

Gao J, He XC, Liu YL, Yao PP, Guan JP, Chen K, Xiang HY, and Yang H

Abstract

Herein, a dual photoredox/nickel catalyzed formylation of aryl bromide with commercially available 2,2-dimethoxy- N , N -dimethylethan-1-amine as an effective CO source has been successfully achieved, delivering a series of aromatic aldehydes in moderate to good yields. Compared with the traditional reductive carbonylation process, this newly designed synthetic protocol provides a straightforward toolbox to access aromatic aldehydes, obviating the use of carbon monoxide and stoichiometric reductants. Finally, the utility of this direct formylation reaction was demonstrated in the pharmaceutical analogue synthesis.

Published
2024
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19. Photoexcited Ni II -Aryl Complex-Mediated Giese Reaction of Aryl Bromides.

Author

He XC, Li KR, Gao J, Guan JP, Chen HB, Xiang HY, Chen K, and Yang H

Subjects
Catalysis, Nickel, Electrons, Bromides, Alkenes
Abstract

A Giese reaction of aryl bromides with electron-deficient alkenes was developed, enabled by a dual catalyst system containing Ni II complex and Ir III photocatalyst. This protocol could accommodate a variety of aryl bromides and electron-deficient alkenes, delivering the conjugate adducts in up to 97% yield. The utilization of photoexcited (dtbbpy)Ni II (aryl)Br intermediate as an aryl radical source allows this novel transformation of aryl halides, thus expanding the chemical space of excited nickel catalysis.

Published
2023
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