Interaction of nitroalkane anions with superelectrophilic 4,6-dinitrobenzofuroxan: σ-adduct formation and vicarious heteroaromatic substitution of hydrogen

Terrier, François; Goumont, Régis; Pouet, Marie‐José; Hallé, Jean-Claude

doi:10.1039/p29950001629

Cited by 43 publications

(38 citation statements)

References 77 publications

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“…[1- 11,36,37] 2) The presence of a lowfield resonance at d = 9.32 ppm assignable to the H13 proton of the exocyclic moiety of 9. This proton is strongly deshielded by the electron-withdrawing effect of the positively charged oxygen atom of the trimethylsilyloxy group.…”

Section: H-mentioning

confidence: 99%

The Diels–Alder Reaction of 4,6‐Dinitrobenzofuroxan with 1‐Trimethylsilyloxybuta‐1,3‐diene: A Case Example of a Stepwise Cycloaddition

Lakhdar

Terrier

Vichard

et al. 2010

Chemistry A European J

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The reaction of 4,6-dinitrobenzofuroxan (DNBF) with 1-trimethylsilyloxybuta-1,3-diene (8) is shown to afford a mixture of [2+4] diastereomeric cycloadducts (10, 11) through stepwise addition-cyclization pathways. Zwitterionic intermediate sigma-adduct 9, which is involved in the processes, has been successfully characterized by (1)H and (13)C NMR spectroscopy and UV/visible spectrophotometry in acetonitrile. A kinetic study has been carried out in this solvent that revealed that the rate of formation of 9 nicely fits the three-parameter equation log k=s(E+N) developed by Mayr to describe the feasibility of nucleophile-electrophile combinations. This significantly adds to the NMR spectroscopic evidence that the overall cycloadditions take place through a stepwise mechanism. The reaction has also been studied in dichloromethane and toluene. In these less polar solvents, the stability of 9 is not sufficient to allow direct characterization by spectroscopic methods, but a kinetic investigation supports the view that stepwise processes are still operating. An informative comparison of our reaction with previous interactions firmly identified as prototype stepwise cycloadditions is made on the basis of the global electrophilicity index, omega, defined by Parr within the density functional theory, and highlighted by Domingo et al. as a powerful tool for understanding Diels-Alder reactions.

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Section: H-mentioning

confidence: 99%

The Diels–Alder Reaction of 4,6‐Dinitrobenzofuroxan with 1‐Trimethylsilyloxybuta‐1,3‐diene: A Case Example of a Stepwise Cycloaddition

Lakhdar

Terrier

Vichard

et al. 2010

Chemistry A European J

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“…Also diagnostic of the addition of the diene molecule at C4-C5 is the presence in the 13 C NMR spectra of a signal (δ = 87.1 ppm for 7b,Et,DMB) that can be assigned to the nitro-substituted quaternary sp 3 carbon C4. [25] Thus, only the N-alkylated compounds 7a-b,Me and 7a-b,Et react with 2,3-dimethylbutadiene to afford the corresponding adducts.…”

Section: Reactions Of 7bet With 23-dimethylbutadiene (Dmb)mentioning

confidence: 99%

The N‐Alkylation of Substituted 4‐Tetrazolo[1,5‐a]pyridines: Easy Access to a New Series of Electrophiles

et al. 2011

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A new series of homoleptic alkynyl complexes, [{Au2Cu2(C2R)4}n] (R=C3H7O (1), C6H11O (2), C9H19O (3), C13H11O (4)), were obtained from Au(SC4H8)Cl, Cu(NCMe)4PF6, and the corresponding alkyne in the presence of a base (NEt3). Complexes 1–4 aggregate upon crystallization into polymeric chains through extensive metallophilic interactions. The cluster that contains fluorenolyl functionalities, C13H9O (5), crystallizes in its molecular form as a disolvate, [Au2Cu2(C2C13H9O)4]⋅2 THF. The substitution of weakly bound THF molecules with pyridine molecules leads to the complex [Au2Cu2(C2C13H9O)4]⋅2 py (6), thus giving two polymorphs in the solid state. Such structural diversity is established through metal‐chain and hydrogen‐bond formation, which depends on the stereochemical characteristics of the organic ligands. More interestingly, this solid‐state structural arrangement affords good emission properties, such as intensity and spectroscopic profile, which are otherwise very weakly emissive in solution. Metallophilic aggregation of the {Au2Cu2} cluster units, as observed in the crystals, results in dramatic enhancement of the room‐temperature phosphorescence, thereby reaching a maximum quantum efficiency of 95 % (4). A theoretical approach further indicates a synergistic effect of the array of the metal chain upon aggregation, which greatly enhances the spin‐orbit coupling and, hence, the phosphorescence, thereby opening up a new direction in the field of aggregate‐enhanced emission.

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“…[25] Its free energy barrier ΔG* is of 20.5 kcal mol -1 . Curiously, for an homologue of the studied compound DNBF, the 4-nitro7-methylbenzofuroxan (NBF) which differs only by the presence of one and not two nitro functions, the two σ complexes result from the addition of the methoxide ions on the carbon atoms C5 and C7 (scheme 1) [26] were identified in competition with the carbanion NBF - [27]. In this work, we have performed quantum calculations in order to test if DNBF follows similar behavior to NBF.…”

Section: Introductionmentioning

confidence: 99%

Theoretical investigation of methoxide ion reaction on the 7-methyl-4,6-dinitrobenzofuroxan

2016

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Reaction of the methoxide ion on the 7-methyl 4,6-dinitrobenzofuroxan (DNBF) 1 has been studied theoretically by means of DFT/B3LYP technique in order to interpret the kineticthermodynamic competition between the three possible compounds that are carbanion DNBF -4 and two complexed forms (2, 3) of the methoxide group in positions 5 and 7 respectively. Optimized Geometry, nbo atomic charge distribution, thermodynamic/kinetic parameters (∆ r H°T, ∆ r S°T , ∆ r G°T, ∆H*, ∆S* and ∆G*) and IRC path have been calculated for possible products and their transitional states using water as solvent. All obtained ∆ r G°T are negative, ranging from -19.16 to -42.87 kcal mol -1 , indicating the possible observation of all products but the experimenters only detected the anionic form DNBF -. Fukui indices, which were calculated by means of NBO atomic charge distribution, confirm the electrophilicity of the sites C5 and C7. Transition states barriers, ΔG* are 14.97 , 15.16 and 21.94 kcal mol -1 for the three possible products 2, 3 and 4 respectively in water. As expected, the most stable compound is the carbanion but it exhibits also the highest activation barrier. If this situation engenders formally a double kinetic-thermodynamic competition, the very weak activation energy of the two complexes in C5 and C7 makes improbable the simultaneous detection of the three expected compounds.

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Interaction of nitroalkane anions with superelectrophilic 4,6-dinitrobenzofuroxan: σ-adduct formation and vicarious heteroaromatic substitution of hydrogen

Cited by 43 publications

References 77 publications

The Diels–Alder Reaction of 4,6‐Dinitrobenzofuroxan with 1‐Trimethylsilyloxybuta‐1,3‐diene: A Case Example of a Stepwise Cycloaddition

The Diels–Alder Reaction of 4,6‐Dinitrobenzofuroxan with 1‐Trimethylsilyloxybuta‐1,3‐diene: A Case Example of a Stepwise Cycloaddition

The N‐Alkylation of Substituted 4‐Tetrazolo[1,5‐a]pyridines: Easy Access to a New Series of Electrophiles

Theoretical investigation of methoxide ion reaction on the 7-methyl-4,6-dinitrobenzofuroxan

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