On the question of zwitterionic intermediates in 1,3-dipolar cycloadditions between hexafluoroacetone and sterically crowded diazocompounds

Jasiński, Radomir

doi:10.1016/j.jfluchem.2015.04.020

Cited by 15 publications

(7 citation statements)

References 34 publications

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“…Additionally, based on the GEDT [46] values (0.0 e), none of the MCs are charge-transfer complexes. Similar molecular complexes were observed in the 32CA reactions between allenyl-type TACs and nitroacetylene [57], benzonitrile N-oxides and nitroethene [55], as well as between diazocompounds and hexafluoroacetone [58].…”

Section: Critical Structuressupporting

confidence: 70%

Regioselectivity, stereoselectivity, and molecular mechanism of [3 + 2] cycloaddition reactions between 2-methyl-1-nitroprop-1-ene and (Z)-C-aryl-N-phenylnitrones: a DFT computational study

et al. 2018

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Reaction paths for [3 + 2] cycloaddition (32CA) between 2-methyl-1-nitroprop-1-ene and (Z)-C-aryl-N-phenylnitrones were explored in detail at the B3LYP/6-31G(d) level of theory. All of the 32CA processes considered were found to be initiated by the attack of the most nucleophilic oxygen atom in the nitrone molecule on the most electrophilic carbon atom (Cβ) in the nitroethylene moiety. This type of interaction favors the formation of 4-nitro-substituted cycloadducts. Additionally, based on a molecular electron density theory (MEDT) study, the 32CA processes of interest should be considered polar processes with asynchronous transition states (TSs). However, the asynchronicity of the localized TSs is unexpectedly low and clearly insufficient to enforce a stepwise zwitterionic mechanism.

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Section: Critical Structuressupporting

confidence: 70%

Regioselectivity, stereoselectivity, and molecular mechanism of [3 + 2] cycloaddition reactions between 2-methyl-1-nitroprop-1-ene and (Z)-C-aryl-N-phenylnitrones: a DFT computational study

et al. 2018

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“…Reactions between allenyl-type 1,3 dipoles and ethylene/acetylene derivatives proceed generally according to the cycloaddition scheme [ 27 – 39 ]. Unexpectedly, diazafluorene reacts with ( E )-2-aryl-1-cyano-1-nitroethenes via another mechanism.…”

Section: Discussionmentioning

confidence: 99%

Unexpected course of reaction between (E)-2-aryl-1-cyano-1-nitroethenes and diazafluorene: why is there no 1,3-dipolar cycloaddition?

et al. 2017

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Reactions between (E)-2-aryl-1-cyano-1-nitroethenes and diazafluorene lead to acyclic 2,3-diazabuta-1,3-diene derivatives, instead of the expected pyrazoline systems. DFT calculations suggest that this is a consequence of formation of zwitterionic structure in the first stage of the reaction. It must be noted that this is a specific property of the (E)-2-aryl-1-cyano-1-nitroethenes group, in contrast to most other conjugated nitroalkenes.Graphical abstract Electronic supplementary materialThe online version of this article (doi:10.1007/s00706-016-1893-5) contains supplementary material, which is available to authorized users.

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“…A reaction with dimethyl acetylenedicarboxylate (25) leads to synthesis of 3,3-diphenylenepyrazolenine dicarbonic acid-(4,5)-dimethyl ester (26) under the same conditions [14]. A synthesis with ditert-buthyl acetylenedicarboxylate (27) as dipolarophile is carried out in a similar manner. The processes is realised at a temperature of 25 o C and benzene as a solvent [19].…”

Section: Reactions Of Diazafluorene With Dipolarophiles Which Has -C≡mentioning

confidence: 99%

“…Those connections are valuable from a practical perspective [1][2][3][4][5][6][7][8][9][10]. In addition, cycloaddition with diazafluorene allows synthesis of spatially crowded groups of spiro-pyrazolines, an adduct otherwise hard to produce [27].…”

Section: Introductionmentioning

confidence: 99%

Diazafluorene in 1,3-dipolar cycloaddiction reactions: short review

2018

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On the question of zwitterionic intermediates in 1,3-dipolar cycloadditions between hexafluoroacetone and sterically crowded diazocompounds

Cited by 15 publications

References 34 publications

Regioselectivity, stereoselectivity, and molecular mechanism of [3 + 2] cycloaddition reactions between 2-methyl-1-nitroprop-1-ene and (Z)-C-aryl-N-phenylnitrones: a DFT computational study

Regioselectivity, stereoselectivity, and molecular mechanism of [3 + 2] cycloaddition reactions between 2-methyl-1-nitroprop-1-ene and (Z)-C-aryl-N-phenylnitrones: a DFT computational study

Unexpected course of reaction between (E)-2-aryl-1-cyano-1-nitroethenes and diazafluorene: why is there no 1,3-dipolar cycloaddition?

Diazafluorene in 1,3-dipolar cycloaddiction reactions: short review

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