Cyclisation intramoléculaire des acides benzyl-2 pentène-4 oïques. Préparation de quelques tétraméthylnaphtalènes

1967 ◽  
Vol 45 (11) ◽  
pp. 1267-1274 ◽  
Author(s):  
P. Canonne ◽  
A. Regnault
Keyword(s):  
Lewis Acids ◽  
Aluminium Chloride ◽  
Methyl Groups ◽  
Secondary Reactions

The cyclization of 2-benzyl-4-pentenoic acids, catalyzed by protonic and Lewis acids, resulted in the formation of variable quantities of α-benzyl-γ-valerolactones and tetrahydronaphthalenecarboxylic acids (65 – 85%) which, after reduction and dehydrogenation, yielded tetramethylnaphthalenes substituted in the 1,3-positions. 1,3,5,7-Tetramethylnaphthalene, in particular, had not as yet been described. Aluminium chloride favors cyclization and does not give rise to lactonization, but it induces secondary reactions such as the migration of methyl groups.

scholarly journals Phosphorous(v) Lewis acids: water/base tolerant P3-trimethylated trications

2018 ◽  
Vol 54 (88) ◽  
pp. 12467-12470 ◽  
Author(s):  
J. M. Bayne ◽  
V. Fasano ◽  
K. M. Szkop ◽  
M. J. Ingleson ◽  
D. W. Stephan
Keyword(s):  
Lewis Acids ◽  
Methyl Groups ◽  
Water Base ◽  
Phosphonium Cations

The water/base intolerance of the previously reported electrophilic phosphonium cations has been overcome by replacing the labile electron-withdrawing groups generally attached to phosphorus (e.g. –F, –OAr, –CF3) with methyl groups.

scholarly journals Orthoamide, LXIII [1]. Tris(dichlormethyl)amin, ein neues breit anwendbares Formylierungsmittel für Aromaten / Orthoamides, LXIII [1]. Tris(dichloromethyl)amine, a New Formylating Reagent for Aromatic Compounds of Wide Scope

2006 ◽  
Vol 61 (4) ◽  
pp. 448-463 ◽  
Author(s):  
Willi Kantlehner ◽  
Ralf Kreß ◽  
Franziska Zschach ◽  
Jens Vetter ◽  
Georg Ziegler ◽  
...  
Keyword(s):  
Aluminum Chloride ◽  
Aromatic Compounds ◽  
Lewis Acids ◽  
Aluminium Chloride ◽  
Aromatic Nucleus ◽  
Wide Scope ◽  
Formyl Group ◽  
Reaction Conditions ◽  
Optimal Reaction

The reagent system formed from tris(dichloromethyl)amine (5) and aluminium chloride allows the formylation of aromatic compounds. The scope of the method is comparable with that of the Olah formylation and the Groß-Rieche procedure, since benzene and even chlorobenzene can be formylated. One formyl group is transferred from 5 to the aromatic nucleus. In order to find optimal reaction conditions, the molar amounts of aromatic compounds, 5 and aluminum chloride were varied as well as reaction temperatures and solvents. The activation of 5 with other Lewis acids is also described

scholarly journals Crystal structures of titanium–aluminium and –gallium complexes bearing twoμ2-CH3units

2017 ◽  
Vol 73 (5) ◽  
pp. 691-693 ◽  
Author(s):  
Tim Oswald ◽  
Mira Diekmann ◽  
Annika Frey ◽  
Marc Schmidtmann ◽  
Rüdiger Beckhaus
Keyword(s):  
Single Crystal ◽  
Crystal Structures ◽  
Lewis Acids ◽  
Methyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Methyl Methyl ◽  
Low Valent ◽  
Titanium Aluminium ◽  
Gallium Complexes

The isotypic crystal structures of two titanocene complexes containing anEMe3unit (E =Al, Ga; Me = methyl) with twoμ2-coordinating methyl groups, namely [μ-1(η5)-(adamantan-1-yl-2κC1)cycylopentadienyl]di-μ2-methyl-methyl-2κC-[1(η5)-pentamethylcyclopentadienyl]aluminiumtitanium(III), [AlTi(CH3)3(C10H15)(C15H18)], and [μ-1(η5)-(adamantan-1-yl-2κC1)cycylopentadienyl]di-μ2-methyl-methyl-2κC-[1(η5)-pentamethylcyclopentadienyl]galliumtitanium(III), [GaTi(CH3)3(C10H15)(C15H18)], are reported. Reacting a dinuclear nitrogen-bridged low-valent titanium(III) complex with the Lewis acids AlMe3or GaMe3results in the loss of molecular dinitrogen and the formation of two monomeric titanocene(III) fragments bearing twoμ2-bridging methyl groups. Single crystal X-ray diffraction reveals the formation of a newE—C bond involving the pentafulvene ligand while the bridging and terminal methyl groups remain intact.

Reactions of β-diketone compounds with nitriles catalyzed by Lewis acids: a simple approach to β-enaminone synthesis

RSC Advances ◽  
2014 ◽  
Vol 4 (109) ◽  
pp. 63897-63900 ◽  
Author(s):  
Xu Cheng ◽  
Shuchen Pei ◽  
Chenchen Xue ◽  
Kaifei Cao ◽  
Li Hai ◽  
...  
Keyword(s):  
Lewis Acids ◽  
Simple Approach ◽  
Aluminium Chloride ◽  
Nucleophilic Attack

Aluminium chloride selectively promoted the nucleophilic attack of β-diketone compounds with nitriles to give enaminones.

The use of homogeneous and heterogeneous Lewis acids to catalyse the photoisomerizations of phenols

1985 ◽  
Vol 63 (12) ◽  
pp. 3449-3455 ◽  
Author(s):  
Satish K. Chadda ◽  
Ronald F. Childs
Keyword(s):  
Oxygen Atom ◽  
Lewis Acid ◽  
Equilibrium Position ◽  
Lewis Acids ◽  
Methyl Groups ◽  
Substituted Phenols ◽  
Keto Form ◽  
Ring Carbon ◽  
Bicyclic Ketones

The reaction of methyl substituted phenols with CH2Cl2 solutions of Al2Br6, leads to the formation of two types of complexes. In both of these the aluminum is bound to the oxygen atom of the phenol but they differ in that the OH proton can either remain on oxygen, oxonium complex, or migrate to one, usually the para, ring carbon, keto complex. The equilibrium position between the two types of complex depends on the position of the methyl groups. Irradiation of a complex of the keto type leads initially to the formation of a complexed bicyclo[3.1.0]hexenone and subsequently to the formation of an isomeric complexed phenol. Only in the case of the tetramethylphenols is the yield of the bicyclic ketone high enough to warrant the use of this photoisomerization as a preparative procedure, although the technique can be used to isomerize a range of phenols to their 4-substituted isomers. The photoisomerizations are not restricted to the use of a homogeneous Lewis acid such as Al2Br6 but heterogeneous aluminosilicates can also be used. The adsorption of 2,3,5,6-tetramethylphenol,1h, on an aluminosilicate was monitored quantitatively and it was shown that a monolayer was formed in which the phenol was at least partially present in the keto form. Irradiation of 1h in the presence of stirred slurries of the aluminosilicate led to the formation of 2,3,4,6-tetramethylphenol. No bicyclic ketones were present in the contacting solution but traces were detected on the catalyst when the irradiations were carried out on adsorbed material in the absence of a solvent. In the case of heterogeneous acids, the selectivity in the adsorption of the starting phenol and the photoproducts is important in determining the composition of the final mixture

scholarly journals Methyl groups as widespread Lewis bases in noncovalent interactions

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Oliver Loveday ◽  
Jorge Echeverría
Keyword(s):  
Electron Density ◽  
Lewis Acids ◽  
Alkaline Earth ◽  
Noncovalent Interactions ◽  
Theoretical Calculations ◽  
Methyl Groups ◽  
Halogen Bonds ◽  
Common Pattern ◽  
Lewis Bases ◽  
Significant Strength

AbstractIt is well known that, under certain conditions, C(sp3) atoms behave, via their σ-hole, as Lewis acids in tetrel bonding. Here, we show that methyl groups, when bound to atoms less electronegative than carbon, can counterintuitively participate in noncovalent interactions as electron density donors. Thousands of experimental structures are found in which methyl groups behave as Lewis bases to establish alkaline, alkaline earth, triel, tetrel, pnictogen, chalcogen and halogen bonds. Theoretical calculations confirm the high directionality and significant strength of the interactions that arise from a common pattern based on the electron density holes model. Moreover, despite the absence of lone pairs, methyl groups are able to transfer charge from σ bonding orbitals into empty orbitals of the electrophile to reinforce the attractive interaction.

Structure of donor-acceptor complexes. X. Complexes of cyanoacetamide with Lewis acids

1969 ◽  
Vol 22 (7) ◽  
pp. 1381 ◽  
Author(s):  
RC Paul ◽  
SL Chadha
Keyword(s):  
Oxygen Atom ◽  
Spectral Data ◽  
Infrared Spectra ◽  
Lewis Acids ◽  
Far Infrared ◽  
Carbonyl Oxygen ◽  
Aluminium Chloride ◽  
Infrared Spectral ◽  
Donor Acceptor ◽  
Ionic Nature

Complexes of cyanoacetamide with aluminium chloride and bromide, anti- mony(V) chloride, boron(III) bromide, tin(IV) chloride and bromide, titanium(IV) chloride and bromide, and zirconium(IV) chloride have been prepared. The molar conductances of the complexes in nitrobenzene indicate their non-ionic nature. The infrared spectra indicate bonding of the metal halides to the carbonyl oxygen atom of the ligand. Metal- to-oxygen bonding also gets support from the far-infrared spectral data.

Chemistry of the Coccoidea. IX. Pigments from the lac insect Austrotachardia acaciae (Hemiptera) and associated synthetic work

1981 ◽  
Vol 34 (11) ◽  
pp. 2481 ◽  
Author(s):  
DW Cameron ◽  
GI Feutrill ◽  
RL Karge ◽  
AF Patti
Keyword(s):  
Aluminium Chloride ◽  
Methyl Groups ◽  
Lac Insect ◽  
Derivatives Of ◽  
Synthetic Work

Minor pigments of the lacciferid Austrotachardia acaciae Maskell include isoerythrolaccin and the new 7-hydroxyerythrolaccin whose structure was confirmed by synthesis. Severe treatment of certain derivatives of 1,3-dihydroxyanthraquinone with aluminium chloride has resulted in novel deoxygenation to the 1-hydroxy series. The 1,2-dimethyl anthraquinones, 3,6,8-trihydroxy-1,2-dimethylanthraquinone and 3,6,7,8-tetrahydroxy-1,2-dimethylanthraquinone, have been synthesized. Oxidation of the methyl groups has been explored as a possible route to the synthesis of the major pigment from A. acaciae, xantholaccaic acid B.

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