Unexpected outcome of NbCl5-promoted Sakurai reaction: Mechanistic implications relevant to C4H7+ species

Maeta, Hideki; Nagasawa, Tetsuya; Handa, Y.; Takei, Toru; Osamura, Yoshihiro; Suzuki, Keisuke

doi:10.1016/0040-4039(94)02332-6

Cited by 37 publications

(12 citation statements)

References 12 publications

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“…While, in the 8-membered ring, the acetals with an allylsilane group only cyclized to methylcycloctene. Our results for the relative stability are in line with the experimental [1][2][3][4][5][6][7][8][9][10] and theoretical [12][13][14][15][16] results. Conclusionally, the relative potential energies of the 6-and 7-membered cyclic products with an exocyclic double bond are similar to those of the methylcycloalkene products with a double bond on the cyclic frame.…”

supporting

confidence: 80%

Relative Stability for the Structural Isomers of Producing Fused-Ring Systems from Acyclic Substrates : Ab Initio Study

2002

Bulletin of the Korean Chemical Society

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Electrophilic substitution reactions of the molecules with an allylsilane group have been extensively applied to the organic synthesis. [1][2][3][4][5][6][7][8][9][10] In particular, the electrophilic reactions of acyclic polyolefins having the allylsilane have been applied to the synthesis of 6-, 7-, 8-, and 9-membered cyclic compounds. In the 6-, 7-, and 9-membered cyclic products, the methylenecycloalkanes with an exocyclic double bond are synthesized, while, in the 8-membered cyclic products, the 7-methoxy-1-methylcycloctene with a double bond on the cyclic skeleton is synthesized.In the experiments of van der Gen et al., 1 the acyclic aldehyde having no allylsilane group under methanol conditions was completely cyclized to a cyclic olefin having a double bond. That is, the cyclization of 5-methyl-5-hexenal gives all three possible alkene isomers (endo-and exo-cyclic delocalized isomers) of 6-membered cyclic compound. Meanwhile, in the experiments of Fleming et al.,2-4 the acyclic acetals with an allylsilane and vinylsilane groups cyclized to give the methylenecyclohexane and methylcyclohexene, respectively. Recently, by the experimental results of Kang et al.,[8][9] Lewis acid-induced intramolecular annulation of the allylsilanes with an electrophilic group was applied to a regioselective formation of several cyclic systems. The cyclizations of the acyclic alkenes with an allylsilane group give the methylenecyclohexane, methylenecycloheptane, methylcycloctene, and methylenecyclononane, respectively. That is, in these cyclizations, the site of the double bond has been controlled by the number of the carbon atoms in acyclic skeleton.By the above experimental results, in the 6-membered cyclic products, the methylenecyclohexane with an exocyclic double bond and the methylcyclohexene with a double bond on the cyclic skeleton are synthesized. While, in the 8-membered cyclic products, the methylcycloctene with a double bond on the ring is easily synthesized. To analyze the experimental findings, we carried out systematic calculations for the 6-, 7-, and 8-membered cyclic compounds with the same accuracy. The geometrical structures of the cyclic compounds are fully optimized using ab initio HartreeFock (HF) and second-order Mφller-Plesset (MP2) methods with the 6-311+G ** basis set. After the optimization, the harmonic vibrational frequencies of those compounds are evaluated to confirm the existence of a stable structure at the HF/6-311+G ** level. The Gaussian 94 program was used. 11We represented the relative stabilities and structures of the cyclic compounds calculated with the MP2/6-311+G ** level. Three schematic potential energy diagrams and optimized structures for the structural isomers of the 6-, 7-, and 8-membered cyclic compounds are drawn in Figure 1. All optimized geometrical structures of the cyclic compounds are local minima without an imaginary frequency. The geometrical isomers of the 6-, 7-, and 8-membered cyclic compounds with higher potential energy are not represented. The structures of the cy...

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confidence: 80%

Relative Stability for the Structural Isomers of Producing Fused-Ring Systems from Acyclic Substrates : Ab Initio Study

2002

Bulletin of the Korean Chemical Society

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“…Suzuki reported relevant NbCl 5 ‐promoted Hosomi–Sakurai reactions in 1995 13. The results of the reaction between 3‐phenylpropionaldehyde and allylsilane in the presence of various early‐transition‐metal halides are shown in Scheme .…”

Section: Use Of Nbv Complexes As Lewis Acidsmentioning

confidence: 99%

Layer‐by‐Layer Assemblies of Catechol‐Functionalized TiO₂ Nanoparticles and Porphyrins through Electrostatic Interactions

Burger

Costa

Lobaz

et al. 2015

Chemistry A European J

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In the current work, we present the successful functionalization and stabilization of P-25 TiO2 nanoparticles by means of N1,N7-bis(3-(4-tert-butyl-pyridium-methyl)phenyl)-4-(3-(3-(4-tert-butyl-pyridinium-methyl)phenylamino)-3-oxopropyl)-4-(3,4-dihydroxybenzamido)heptanediamide tribromide (1). The design of the latter is aimed at nanoparticle functionalization and stabilization with organic building blocks. On one hand, 1 features a catechol anchor to enable its covalent grafting onto the TiO2 surface, and on the other hand, positively charged pyridine groups at its periphery to prevent TiO2 agglomeration through electrostatic repulsion. The success of functionalization and stabilization was corroborated by thermogravimetric analysis, dynamic light-scattering, and zeta potential measurements. As a complement to this, the formation of layer-by-layer assemblies, which are governed by electrostatic interactions, by alternate deposition of functionalized TiO2 nanoparticles and two negatively charged porphyrin derivatives, that is, 5,10,15,20-(phenoxyacetic acid)-porphyrin (2) and 5,10,15,20-(4-(2-ethoxycarbonyl)-4-(2-phenoxyacetamido)heptanedioic acid)-porphyrin (3), is documented. To this end, the layer-by-layer deposition is monitored by UV/Vis spectroscopy, scanning electron microscopy, ellipsometry, and profilometry techniques. The resulting assemblies are utilized for the construction and testing of novel solar cells. From stable and repeatable photocurrents generated during several "on-off" cycles of illumination, we derive monochromatic incident photo-to-current conversion efficiencies of around 3 %.

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“…For example, they are known to react with carbon-nitrogen, [1,2] carbon-oxygen [3,4] and carboncarbon multiple bonds [5,6] to give 1,2-dianion or radical species. On the other hand, recent studies of Nb V have focused on organic transformations in carbon-carbon bond formation which are typical Lewis acid-mediated reactions, [7][8][9] except for unique reactions such as cyclopropane formation [10] and dealkylative acylation. [11] We were interested in the strong Lewis acidity of Nb V , and started to investigate its unique reactivity.…”

Section: Introductionmentioning

confidence: 99%

Facile and Regioselective Dealkylation of Alkyl Aryl Ethers Using Niobium(V) Pentachloride

2006

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Unexpected outcome of NbCl5-promoted Sakurai reaction: Mechanistic implications relevant to C4H7+ species

Cited by 37 publications

References 12 publications

Relative Stability for the Structural Isomers of Producing Fused-Ring Systems from Acyclic Substrates : Ab Initio Study

Relative Stability for the Structural Isomers of Producing Fused-Ring Systems from Acyclic Substrates : Ab Initio Study

Layer‐by‐Layer Assemblies of Catechol‐Functionalized TiO₂ Nanoparticles and Porphyrins through Electrostatic Interactions

Facile and Regioselective Dealkylation of Alkyl Aryl Ethers Using Niobium(V) Pentachloride

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Unexpected outcome of NbCl5-promoted Sakurai reaction: Mechanistic implications relevant to C4H7+ species

Cited by 37 publications

References 12 publications

Relative Stability for the Structural Isomers of Producing Fused-Ring Systems from Acyclic Substrates : Ab Initio Study

Relative Stability for the Structural Isomers of Producing Fused-Ring Systems from Acyclic Substrates : Ab Initio Study

Layer‐by‐Layer Assemblies of Catechol‐Functionalized TiO2 Nanoparticles and Porphyrins through Electrostatic Interactions

Facile and Regioselective Dealkylation of Alkyl Aryl Ethers Using Niobium(V) Pentachloride

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Layer‐by‐Layer Assemblies of Catechol‐Functionalized TiO₂ Nanoparticles and Porphyrins through Electrostatic Interactions