Iodine-Catalyzed Regioselective Oxidative Cyclization of Aldehyde Hydrazones with Electron-Deficient Olefins for the Synthesis of Mefenpyr-Diethyl

Zhu, Jia-Nan; Wang, Wen-Kang; Zheng, Jian; Lin, Hao-Peng; Deng, Yunxia; Zhao, Sheng‐Yin

doi:10.1021/acs.joc.9b01499

Cited by 6 publications

(2 citation statements)

References 73 publications

(79 reference statements)

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“…The reagents were purchased from commercial chemical reagent companies and used without further purification unless otherwise stated. Hydrazones 1 and 1,3-diarylpropenes 2 were prepared according to the literatures.…”

Section: Methodsmentioning

confidence: 99%

Metal-Free Tandem Oxidative Cyclization for the Synthesis of 1,2-Dihydropyridazines and Pyrazoles

Cheng

Shen

et al. 2021

J. Org. Chem.

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Mediated by 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), a novel oxidative coupling of hydrazones and 1,3-diarylpropenes has been disclosed to generate appealing β,γ-unsaturated hydrazones, which further undergo 5-exo-trig or 6-endo-trig cascade cyclization to give the respective 1,2-dihydropyridazines or pyrazoles selectively under metal-free conditions. The mechanisms of the coupling and subsequent cyclization are proposed.

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Section: Methodsmentioning

confidence: 99%

Metal-Free Tandem Oxidative Cyclization for the Synthesis of 1,2-Dihydropyridazines and Pyrazoles

Cheng

Shen

et al. 2021

J. Org. Chem.

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“…A protocol that could effectively construct polysubstituted dihydropyrazoles and pyrazoles via iodinemediated CÀ H functionalization, CÀ N bond formation, and oxidation of aldehyde hydrazones 369 and electron-deficient olefins 370 was achieved by the Zhao group in 2019 (Scheme 58a). [108] Later, Wu and Shu revealed a molecular iodine-induced metal-free cascade [4 + 1] cyclization reaction that can synthesize 4aryl-NH-1,2,3-triazoles using N-tosylhydrazones 373 and sodium azide 374 as starting materials (Scheme 58b). [109] In 2020, an iodine-promoted selective cyclization reaction of N-tosylhydrazones 376 with sulfur 377 that can efficiently construct 4-aryl-1,2,3-thiadiazoles was proposed by Gu's group.…”

Section: Iodine-mediated Intermolecular Cyclizationmentioning

confidence: 99%

Update on the Synthesis of N‐Heterocycles via Cyclization of Hydrazones (2017–2021)

Meng

et al. 2021

Adv Synth Catal

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Hydrazones, as universal structural units, are useful synthons for the formation of carbonnitrogen and nitrogenÀ heteroatom bonds. Thus, they provide new methods of constructing nitrogen-containing heterocycles. In recent years, especially between 2017 and 2021, many efforts have been made to exploit hydrazone-based reactions in efforts to develop more powerful and effective pathways towards the synthesis of various multifunctional heterocyclic compounds. However, despite the tremendous amount of work that has been published over the past five years, no review has been published that summarizes the significant progress in the preparation of nitrogen heterocycles via intramolecular cyclization of hydrazones with adjacent unsaturated bonds or intermolecular cyclization of hydrazones with unsaturated systems. Therefore, this review summarizes the hydrazone-based cyclization strategies used to synthesize nitrogen-containing heterocycles over the past five years. It discusses the corresponding reaction scopes, limitations, mechanisms, and problems. Cyclization of Hydrazones with Unsaturated Systems 3.3. Cyclization of Hydrazones with Unsaturated Systems Under Metal-Free Conditions 4. Conclusion

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An Oxidative [3+2+1] Cyclization of Enaminones and N‐Alkenyl‐2‐pyrrolidinone: Access to Polysubstituted 4‐Alkylated 1,4‐dihydropyridines

et al. 2023

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An oxidative [3+2+1] cyclization of enaminones and N‐alkenyl‐2‐pyrrolidinone is described for the synthesis of 4‐alkylated 1,4‐dihydropyridines (1,4‐DHPs). By using terminal olefin as the C4 source of the 1,4‐DHP skeleton, this synthetic strategy provides a series of 1,4‐DHPs through a 1,1‐difunctionalization/cyclization process. In this protocol, two C(sp3)−C(sp2) bonds and a C(sp2)−N bond are simultaneously formed, the hydrogen source on the newly formed methyl group of the 1,4‐DHP skeleton is confirmed and a possible mechanism is proposed.

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Iodine-Catalyzed Regioselective Oxidative Cyclization of Aldehyde Hydrazones with Electron-Deficient Olefins for the Synthesis of Mefenpyr-Diethyl

Cited by 6 publications

References 73 publications

Metal-Free Tandem Oxidative Cyclization for the Synthesis of 1,2-Dihydropyridazines and Pyrazoles

Metal-Free Tandem Oxidative Cyclization for the Synthesis of 1,2-Dihydropyridazines and Pyrazoles

Update on the Synthesis of N‐Heterocycles via Cyclization of Hydrazones (2017–2021)

An Oxidative [3+2+1] Cyclization of Enaminones and N‐Alkenyl‐2‐pyrrolidinone: Access to Polysubstituted 4‐Alkylated 1,4‐dihydropyridines

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