Oxidation of C–H bonds to CO bonds by O2 only or N-oxides and DMSO: synthesis of Δ1-bipyrrolinones and pyrrolino[3,2-b]pyrrolinones from 2,6-diazasemibullvalenes

Zhang, Shaoguang; Zhan, Mei; Luo, Qian; Zhang, Wen‐Xiong; Xi, Zhenfeng

doi:10.1039/c3cc43061h

Cited by 14 publications

(8 citation statements)

References 39 publications

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“…33,34 Our results showed that O 2 oxidation of NSBV at room temperature affords Δ 1 -bipyrrolinones via C−N bond cleavage and C−H bond oxidation (Scheme 9). 35 C−H bonds are oxidized to CO bonds by oxygen only, without any additives or promoters. 34 1,5-Bridged or nonbridged NSBVs 2 bearing different alkyl or aryl substituents could all be applied in this oxidation reaction, affording Δ 1 -bipyrrolinones 27.…”

Section: Thermolysis Of Nsbvs 2g and 2hmentioning

confidence: 99%

Semibullvalene and Diazasemibullvalene: Recent Advances in the Synthesis, Reaction Chemistry, and Synthetic Applications

Zhang

2015

Acc. Chem. Res.

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Semibullvalene (SBV) and its aza analogue 2,6-diazasemibullvalene (NSBV) are theoretically interesting and experimentally challenging organic molecules because of four unique features: highly strained ring systems, intramolecular skeletal rearrangement, extremely rapid degenerate (aza-)Cope rearrangement, and the predicted existence of neutral homoaromatic delocalized structures. SBV has received much attention in the past 50 years. In contrast, after NSBV was predicted in 1971 and the first in situ synthesis was realized in 1982, no progress on NSBV chemistry was made until our results in 2012. We have been interested in the reaction chemistry of 1,4-dilithio-1,3-butadienes (dilithio reagents for short), especially for their applications in the synthesis of SBV and NSBV, because (i) the cyclodimerization of dilithio reagents could provide the potential eight-carbon skeleton of SBV from four-carbon butadiene units and (ii) the insertion reaction of dilithio reagents with C≡N bonds of two nitriles could provide a 6C + 2N skeleton that might be a good precursor for the synthesis of NSBV. Therefore, we initiated a journey into the synthesis and reaction chemistry of SBV and NSBV starting from dilithio reagents that has been ongoing since 2006. In this Account, we outline mainly our recent achievements in the synthesis, structural characterization, reaction chemistry, synthetic application, and theoretical/computational analysis of NSBV. Two efficient strategies for the synthesis of NSBV from dilithio reagents and nitriles via oxidant-induced C-N bond formation are described. Structural investigations of NSBV, including X-ray crystal structure analysis, determination of the activation barrier for the aza-Cope rearrangement, and theoretical analysis, show that the localized structure of NSBV is the predominant form and that the homoaromatic delocalized structure exists as a minor component in the equilibrium. We also discuss the reaction chemistry and synthetic applications of NSBV. Several novel reaction patterns have been explored, including thermolysis, C-N bond insertion, rearrangement-cycloaddition, oxidation, and nucleophilic ring-opening reactions. Diverse and interesting N-containing polycyclic skeletons can be constructed, such as nickelaazetidine, 1,5-diazatriquinacenes, and triazabrexadienes, which are not available by other means. Our results show that NSBV not only features a rapid aza-Cope rearrangement with a low activation barrier but also acts as unique synthetic reagent that is significantly different from aziridine. The strained rigid ring systems as a whole can be involved in the reactions. Our achievements highlight two significant advances: (i) the well-established efficient synthesis and isolation of NSBV has greatly accelerated the development of NSBV chemistry, and (ii) the previously unattainable molecules have become "normal" and routine starting materials for the synthesis of otherwise unavailable but interesting structures. We expect that our pursuits will inspire and help direct future ch...

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Section: Thermolysis Of Nsbvs 2g and 2hmentioning

confidence: 99%

Semibullvalene and Diazasemibullvalene: Recent Advances in the Synthesis, Reaction Chemistry, and Synthetic Applications

Zhang

2015

Acc. Chem. Res.

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“…These weaknesses underscore the need to develop an efficient method for construction of α-ketoesters that uses cheap and readily available starting materials and reagents. To address these limitations, herein we report a copper-catalyzed aerobic oxidative esterification between aryl methyl ketones and alcohols to form a broad range of α-ketoesters and esters using molecular oxygen 17 as the terminal oxidant.…”

mentioning

confidence: 99%

Cu-Catalyzed Aerobic Oxidative Esterification of Acetophenones with Alcohols to α-Ketoesters

Ding

Lin

et al. 2015

Org. Lett.

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“…The dihedral angle of 88.10°between the two cyclic planes demonstrates a near perpendicular conformation. Copyright 2010 American Chemical Society 66 3 Bulky Nitrile Coordination-Induced Skeleton Rearrangement … zirconacyclopropene moiety. This transformation of silacyclobutenes to azasilacyclopentadienes represents an unprecedented and useful reaction pattern of silacycles [14,15].…”

Section: Bulky Nitriles Coordination-induced Skeleton Rearrangement Omentioning

confidence: 99%

“…Both Δ 1 -bipyrrolones and mono-pyrrolones were further The CCl 4 solution of 6-1a was treated with oxygen (balloon, 1 atm) at room temperature for 12 h (Scheme 6.2). [66] with permission from The Royal Society of Chemistry 6.2 Result and Discussion 141 in situ generated hydrogen peroxide radical would construct two C=O bonds in Δ 1 -bipyrrolinones 6-22. Heating of neat 6-1a to 270°C in open air for about 10 min also afforded 6-22a in 89 % isolated yield.…”

Section: Scandium Triflate-catalyzed Rearrangement-cycloaddition Of 2mentioning

confidence: 99%

The Chemistry of Zirconacycles and 2,6-Diazasemibullvalenes

Zhang

2015

Springer Theses

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Oxidation of C–H bonds to CO bonds by O2 only or N-oxides and DMSO: synthesis of Δ1-bipyrrolinones and pyrrolino[3,2-b]pyrrolinones from 2,6-diazasemibullvalenes

Cited by 14 publications

References 39 publications

Semibullvalene and Diazasemibullvalene: Recent Advances in the Synthesis, Reaction Chemistry, and Synthetic Applications

Semibullvalene and Diazasemibullvalene: Recent Advances in the Synthesis, Reaction Chemistry, and Synthetic Applications

Cu-Catalyzed Aerobic Oxidative Esterification of Acetophenones with Alcohols to α-Ketoesters

The Chemistry of Zirconacycles and 2,6-Diazasemibullvalenes

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