- Divergent synthesis of α-functionalized amides through selective N-O/C-C or N-O/C-C/C-N cleavage of aza-cyclobutanone oxime esters
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Herein, a novel sequential ring opening reaction of aza-cyclobutanone oxime esters with isocyanides is described. The reaction proceeded smoothly under redox-neutral and mild conditions, leading to a divergent synthesis of α-cyanomethylaminoamides, α-acyloxyamides and α-acylaminoamides. In these transformations, a selective N-O/C-C or N-O/C-C/C-N cleavage was achieved only by changing the iron-catalyst system. Among them, a rare sequential N-O/C-C/C-N cleavage process with a classical Passerini or Ugi multicomponent reaction can be executed in a single step. To the best of our knowledge, this work creates a novel reaction mode of cycloketone oximes and provides new opportunities for reaction design.
- Cai, Zhong-Jian,Ji, Shun-Jun,Jiang, Nan-Quan,Li, Hai-Yan,Liu, Hua-Wei,Wang, Dian-Liang
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p. 9618 - 9621
(2021/09/28)
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- Copper-Catalyzed Radical C-C Bond Cleavage and [4+1] Annulation Cascade of Cycloketone Oxime Esters with Enaminothiones
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Carbon-carbon bond formation is among the most important reactions in organic synthesis. Reconstruction of a carbon-carbon bond through ring-opening C-C bond cleavage of a strained carbocycle usually occurs via a thermodynamically preferable pathway. However, carbon-carbon bond formation through thermodynamically less favorable C-C bond cleavage has seldom been documented. Herein, we disclose an unusual C-C bond cleavage of cycloketone oxime esters for [4+1] annulation. Under anaerobic copper(I) catalysis, cycloketone oxime esters underwent regioselective, thermodynamically less favorable radical C-C bond cleavage followed by annulation with enaminothiones; that is, α-thioxo ketene N,S-acetals efficiently affording 2-cyanoalkyl-aminothiophene derivatives. Cyclobutanone, -pentanone, -hexanone, and -heptanone oxime esters could act as the effective C1 building blocks in the annulation reaction. An iminyl radical mechanism is proposed for the rare C-C bond cleavage/[4+1] annulation cascade.
- He, Yuan,Lou, Jiang,Wu, Kaikai,Wang, Hongmei,Yu, Zhengkun
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supporting information
(2019/02/14)
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- Photocatalytic, Phosphoranyl Radical-Mediated N-O Cleavage of Strained Cycloketone Oximes
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A photoinduced, phosphoranyl radical-mediated protocol for the direct N-O cleavage of strained cycloketone oximes via a polar/SET crossover process was developed for the first time. This visible-light-driven direct N-O activation mode for oxime offers beneficial features such as streamlined synthetic process and versatile photochemical reactivities. Consequently, the alkenes and α-trifluoromethyl alkenes with varied electronic and structural features acted as competent radical receptors in this protocol, enabling facile accesses to a range of elongated cyano and/or gem-difluoroalkene-bearing compounds.
- Xia, Peng-Ju,Ye, Zhi-Peng,Hu, Yuan-Zhuo,Song, Dan,Xiang, Hao-Yue,Chen, Xiao-Qing,Yang, Hua
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supporting information
p. 2658 - 2662
(2019/04/25)
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- Nickel-Catalyzed Thiolation and Selenylation of Cycloketone Oxime Esters with Thiosulfonate or Seleniumsulfonate
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A nickel-catalyzed ring opening and, subsequently, reductive cross-coupling of cycloketone oxime esters with thiosulfonate or seleniumsulfonate are reported, which involves C-C bond cleavage and C(sp3)-S or C(sp3)-Se bond formation. Notably, S-aryl/alkyl sulfonothioates and Se-alkyl seleniumsulfonothioates could be employed in this reaction to afford a variety of 1° and 2° alkyl sulfides, aryl sulfides, and 1° and 2° alkyl selenides in one step. This strategy features easily available substrates and mild reaction conditions.
- Li, Jian,Wang, Shun-Yi,Ji, Shun-Jun
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p. 16147 - 16156
(2019/12/27)
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- Novel Syntheses of 1,3,3-Trinitroazetidine
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Alternative methods for the synthesis of 1,3,3-trinitroazetidine (TNAZ) from epichlorohydrin, and benzhydrylamine have been developed.These approaches employ N-sulfonyl-3-(hydroxyimino)azetidines as penultimate intermediates and represent an improvement over previously published methods which require either diazo containing intermediates or involve low yielding procedures.Parallel methods employing N-benzhydryl- and N-benzyl-3-(hydroxyimino)azetidine were also investigated as alternate routes to TNAZ
- Katritzky, Alan R.,Cundy, Darren J.,Chen, Jie
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p. 271 - 276
(2007/10/02)
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