Bis(amino)cyclopropenylidenes as Organocatalysts for Acyl Anion and Extended Umpolung Reactions

Wilde, Myron M. D.; Gravel, Michel

doi:10.1002/ange.201307167

Cited by 20 publications

(10 citation statements)

References 66 publications

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“…Moreover, thermal decomposition ( T dec ) of the tris(dialkylamino)CP chloride salts has been measured at >300 °C 19 , significantly exceeding that of dialkylimidazolium chloride salts ( T dec ~250 °C) 26 . These unique structural features have already inspired the development of aminocyclopropenium ions for a range of applications, including as metal ligands 27 , organocatalysts 28 29 30 and ionic liquids 19 ; however, the incorporation of these cations into a polymeric backbone has only led to polymers with unstable CP ions as intermediates 31 . Given the tunable functionality and robust, efficient and orthogonal chemistry characterizing CP ions, it is desirable to exploit them in polymeric materials.…”

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confidence: 99%

The evolution of cyclopropenium ions into functional polyelectrolytes

et al. 2015

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Versatile polyelectrolytes with tunable physical properties have the potential to be transformative in applications such as energy storage, fuel cells and various electronic devices. Among the types of materials available for these applications, nanostructured cationic block copolyelectrolytes offer mechanical integrity and well-defined conducting paths for ionic transport. To date, most cationic polyelectrolytes bear charge formally localized on heteroatoms and lack broad modularity to tune their physical properties. To overcome these challenges, we describe herein the development of a new class of functional polyelectrolytes based on the aromatic cyclopropenium ion. We demonstrate the facile synthesis of a series of polymers and nanoparticles based on monomeric cyclopropenium building blocks incorporating various functional groups that affect physical properties. The materials exhibit high ionic conductivity and thermal stability due to the nature of the cationic moieties, thus rendering this class of new materials as an attractive alternative to develop ion-conducting membranes.

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confidence: 99%

The evolution of cyclopropenium ions into functional polyelectrolytes

et al. 2015

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“…Vor kurzem berichteten Gravel und Wilde6 über die Synthese des Bertrand‐Salzes 5 und des weniger sperrigen Derivats 12 mithilfe einer modifizierten Literaturmethode (Schema ) 7. Beide Salze wurden anschließend als Präkatalysator für die intermolekulare Stetter‐Reaktion getestet.…”

Section: Methodsunclassified

Synthesis, Crystal Structure, Thermal and Explosive Properties of [Cd(SCZ)₃(H₂O)](PA)₂·3H₂O (SCZ = Semicarbazide, PA = Picrate)

Tong

Zhang²,

Xue

et al. 2015

Zeitschrift anorg allge chemie

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The heptacoordinate transition metal coordination compound [Cd(SCZ)3(H2O)](PA)2·3H2O (1) with the ligand semicarbazide (SCZ) and the counteranion picrate (PA) was synthesized and characterized by elemental analysis and FTIR spectroscopy. Single‐crystal X‐ray diffraction analysis revealed that 1 crystallizes in the monoclinic space group P21/c. The Cd2+ ion is heptacoordinated by three SCZ groups and a water molecule. SCZ presents typical bidentate coordination modes. The thermal decomposition mechanism of 1 was studied by differential scanning calorimetry (DSC), which revealed that complex 1 exhibits three small endothermic and two large exothermic processes. The non‐isothermal kinetics parameters were calculated by the Kissinger's method and Ozawa‐Doyle's method, respectively. The heat of combustion was measured by oxygen bomb calorimetry. The enthalpy of formation, the critical temperature of thermal explosion, the entropy of activation (ΔS≠), the enthalpy of activation (ΔH≠), and the free energy of activation (ΔG≠) were also calculated. Sensitivity tests revealed that 1 is insensitive to mechanical stimuli.

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“…Michael Gravel and his co‐workers comprehensively disclosed the catalytic behaviour of BACs towards intermolecular Stetter [ 61 ] and aza‐Benzoin [ 62 ] reactions. On the other hand, Anand et al [ 63 ] studied an efficient 1,6‐conjugate addition of aromatic aldehyde to para‐quinone methides catalysed by Et‐BAC to produce α , α ˊ‐diarylated ketones.…”

Section: Introductionmentioning

confidence: 99%

“…However, these limitations can be easily overcome by the use of sterically less hindered Et‐BAC catalyst. [ 61 ]…”

Section: Introductionmentioning

confidence: 99%

A density functional theory investigation on bis(diethylamino)cyclopropenylidene catalyzed synthesis of 1,4‐bifunctional compounds

Shyam

Pradhan

Mondal

2021

J of Physical Organic Chem

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Bis(amino)cyclopropenylidenes (BACs) are the newly discovered umpolung catalysts with potential applications in the synthesis of numerous important organic moieties. A plausible mechanism for bis(diethylamino)cyclopropenylidene (Et‐BAC) catalysed synthesis of 1,4‐diketones has been investigated using density functional theory (DFT). The proposed catalytic cycle initiates with the nucleophilic interaction of in situ generated Et‐BAC with p‐methoxybenzaldehyde to form a zwitterionic intermediate, which on proton transfer reaction gives Breslow intermediate. Breslow intermediate then favours 1,4‐umpolung addition reaction with chalcone followed by another proton transfer to regenerate the Et‐BAC along with enolic form of the product. Enolic form ultimately transforms into the desired keto form, 1‐(4‐methoxyphenyl)‐2,4‐diphenylbutane‐1,4‐dione via protonated and free DBU aided proton shift mechanism. DFT‐derived reactivity parameters along with frontier molecular orbital (FMO) analysis have been successfully utilised to reveal the umpolung efficacy of Et‐BAC. This DFT exploration is in good accordance with experimental findings and also offers a deeper insight into the Et‐BAC catalysed organic transformations.

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Bis(amino)cyclopropenylidenes as Organocatalysts for Acyl Anion and Extended Umpolung Reactions

Cited by 20 publications

References 66 publications

The evolution of cyclopropenium ions into functional polyelectrolytes

The evolution of cyclopropenium ions into functional polyelectrolytes

Synthesis, Crystal Structure, Thermal and Explosive Properties of [Cd(SCZ)₃(H₂O)](PA)₂·3H₂O (SCZ = Semicarbazide, PA = Picrate)

A density functional theory investigation on bis(diethylamino)cyclopropenylidene catalyzed synthesis of 1,4‐bifunctional compounds

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Bis(amino)cyclopropenylidenes as Organocatalysts for Acyl Anion and Extended Umpolung Reactions

Cited by 20 publications

References 66 publications

The evolution of cyclopropenium ions into functional polyelectrolytes

The evolution of cyclopropenium ions into functional polyelectrolytes

Synthesis, Crystal Structure, Thermal and Explosive Properties of [Cd(SCZ)3(H2O)](PA)2·3H2O (SCZ = Semicarbazide, PA = Picrate)

A density functional theory investigation on bis(diethylamino)cyclopropenylidene catalyzed synthesis of 1,4‐bifunctional compounds

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Synthesis, Crystal Structure, Thermal and Explosive Properties of [Cd(SCZ)₃(H₂O)](PA)₂·3H₂O (SCZ = Semicarbazide, PA = Picrate)