- Copper-Catalyzed N-Arylation of Nitroenamines with Diaryliodonium Salts
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A novel synthetic methodology was developed for the N-arylation of nitroenamine derivatives utilizing diaryliodonium triflates and copper(I) chloride as a catalyst. The procedure enables the easy aryl transfer from the hypervalent species under mild catalytic conditions with unusual heteroatom preference and high efficiency.
- Aradi, Klára,Mészáros, ádám,Tóth, Balázs L.,Vincze, Zoltán,Novák, Zoltán
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- Cascade nitrosation and addition-elimination of nitroacetanilides for the highly efficient synthesis of 1,4,2,5-dioxadiazine derivatives
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A domino nitrosation and addition-elimination of nitroacetanilides with NaNO2 and H2SO4 has been developed to synthesize a variety of 1,4,2,5-dioxadiazine-3,6-dicarboxamides in excellent yields. The substrate scope can be extended to aryl nitromethyl ketones. A cascade reaction mechanism is proposed and the conjugated aryl moiety is considered to help stabilize the aci-nitroso species, the key intermediates in the cascade reaction. The methodology is practical and efficient because it avoids the purification of the intermediates. The nitroacetanilides were prepared from nitroacetic acid and various anilines employing DCC-DMAP as coupling reagents, and this protocol also possesses advantages like easy handling and high yields. This journal is the Partner Organisations 2014.
- Mo, Shanyan,Huang, Peipei,Xu, Jiaxi
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p. 4192 - 4200
(2014/06/10)
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- Stereoselective control in the Staudinger reactions involving monosubstituted ketenes with electron acceptor substituents: Experimental investigation and theoretical rationalization
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The stereoselectivity of the Staudinger reactions involving monosubstituted ketenes with electron acceptor substituents was investigated experimentally by determination of the product stereochemistry and theoretically via DFT calculations. The results indicate that imines preferentially attack the less sterically hindered exo-side of the ketenes to generate zwitterionic intermediates. Subsequently, for cyclic imines, the intermediates undergo a conrotatory ring closure directly to produce β-lactams, while for linear imines, the imine moiety of the intermediates isomerizes to more stable intermediates, which further undergo a conrotatory ring closure to afford trans-β-lactams. The steric hindrance and the isomerization, rather than the torquoelectronic effect, play crucial roles in controlling the stereoselectivity in the practical Staudinger reactions involving monosubstituted ketenes with electron acceptor substituents, although the unaccessible borylketene with a powerful electron acceptor group controls the stereoselectivity torquoelectronically, in theory.
- Qi, Hengzhen,Li, Xinyao,Xu, Jiaxi
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supporting information; experimental part
p. 2702 - 2714
(2011/05/19)
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- Synthesis of isatin 3-oximes from 2-nitroacetanilides
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2-Nitroacetanilides, prepared by alkaline hydrolysis of 1-arylamino-1-methylthio-2-nitroethenes, are converted into isatin (1H-indole-2,3-dione) 3-oximes by treatment with concentrated sulfuric acid or trifluoromethanesulfonic acid at room temperature.
- Kearney,Harris,Jackson,Joule
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p. 769 - 772
(2007/10/02)
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- Production of carbonyl compounds substituted in α-position
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Production of carbonyl compounds substituted in the α-position and having the formula: EQU1 wherein R1 is alkyl, aralkyl, phenyl, toluyl, naphthyl, alkoxy or amino; R2 is hydrogen EQU2 A is hydrogen, alkyl, halo or EQU3 R6 is hydrogen or methyl, and R11 is alkyl; wherein said compounds are formed by reacting a sulfur ylide having the formula: EQU4 wherein Y is the radical EQU5 and R9 and R10 are alkyl or phenyl, with a solution containing both an electrophilic agent A' that is converted into the radical A and a nucleophilic agent B' that is converted into the radical B. The resulting carbonyl compounds are useful as starting materials for the production of paper, textile, and leather auxiliaries, plant protection agents, alkyd resins, polyesters and polyamides.
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