Study of the mechanism of the reaction of trimethyl-p-hydroquinone and its derivatives with lewis acids under homogeneous conditions by the method of NMR spectroscopy

1985 ◽  
Vol 19 (3) ◽  
pp. 206-209
Author(s):  
M. B. Tarabrin ◽  
V. V. Chupin ◽  
�. Yu. Bulychev ◽  
R. P. Evstigneeva
Keyword(s):  
Nmr Spectroscopy ◽  
Lewis Acids ◽  
Mechanism Of The Reaction

Pentacarbonylmanganese enolate and dienolate complexes. Preparative and mechanistic considerations

1990 ◽  
Vol 68 (3) ◽  
pp. 492-501 ◽  
Author(s):  
Andrew P. Masters ◽  
Ted S. Sorensen
Keyword(s):  
Nmr Spectroscopy ◽  
Nucleophilic Substitution ◽  
Reaction Products ◽  
Organic Products ◽  
Mechanism Of The Reaction ◽  
Model Reactions ◽  
Inorganic And Organic

Reactions of pentacarbonyl manganate anion with 4-halocrotonate esters or 2-halocarboxylate esters result in a complex set of inorganic and organic products, usually including the expected dienolate (or enolate) complexes. The reaction variables include the counterion, solvent, and halo group. The mechanism of the reaction has been investigated by conducting a thorough characterization of the reaction products under various conditions and also by carrying out model reactions. One can rationalize most of the non-organometallic products using either a radical or carbanion mechanism, but the latter seems to fit the available data better. Experimental procedures for optimizing the yield of the organometallic dienolate or enolate complexes have been worked out. Keywords: pentacarbonyl manganate, metalate nucleophilicity, enolate complex, nucleophilic substitution, 55Mn NMR spectroscopy.

Reaktionen von 1-Aryl-3-alkyl-triazenen mit Lewis-Säuren in Benzol / Reactions of 1-Aryl-3-alkyl-triazenes with Lewis Acids in Benzene

1976 ◽  
Vol 31 (2) ◽  
pp. 217-221 ◽  
Author(s):  
Richard Kreher ◽  
Kurt Goth
Keyword(s):  
Lewis Acids ◽  
Substituted Anilines ◽  
Intramolecular Alkylation ◽  
Alkyl Azides ◽  
Alkylation Process ◽  
Alkyl Benzenes ◽  
Mechanism Of The Reaction

The reaction of 1-phenyl-3-alkyl-triazenes with lewis acids in benzene has been examined in order to evaluate the mechanism of the reaction of alkyl azides with electrophiles in benzene. Evolution of nitrogen gives rise to the formation of the corresponding substituted anilines by intramolecular alkylation. Alkyl benzenes are the result of an intermolecular alkylation process.

Etude par resonance magnétique multinucléaire d'intermédiaires réactionnels électrophiles. Partie 8. Action des acides de Lewis chlorés COCl2, POCl3, (CH3)2N=CHCl+Cl− et Cl2 sur l'hexaméthylphosphotriamide (HMPT)

1980 ◽  
Vol 58 (9) ◽  
pp. 946-952 ◽  
Author(s):  
S. Poignant ◽  
J. R. Gauvreau ◽  
G. J. Martin
Keyword(s):  
Nmr Spectroscopy ◽  
Structural Study ◽  
Lewis Acids ◽  
Mechanism Of Formation ◽  
Substitution Product ◽  
Vilsmeier Reagent ◽  
Résonance Magnétique

The structural study of the electrophilic intermediates obtained from carboxamides and chlorinated Lewis acids is extended to the phosphoric amides. The action of COCl2 and POCl3 on hexamethylphosphotriamide (HMPT) can lead to a chlorophosphonium salt (3a) the structure of which is proved by nmr spectroscopy (1H, 13C, 31P, 15N). The mechanism of formation is comparable to that of the chloroiminium chloride (Vilsmeier reagent) from the corresponding amides. The action of chlorine on HMPT does not lead to a stable salt of the same kind but essentially to the substitution product (2). A new biphosphorylated compound (6) has been identified when an excess of chlorine is reacted with HMPT.

Synthesis of heteronuclear bifunctional Lewis acids by transmetalation of 1,8-bis(trimethylstannyl)naphthalene with BCl3

2002 ◽  
Vol 80 (10) ◽  
pp. 1308-1312 ◽  
Author(s):  
Marcus Schulte ◽  
François P Gabbaï
Keyword(s):  
Elevated Temperature ◽  
Nmr Spectroscopy ◽  
Single Crystal ◽  
Acid Derivative ◽  
Lewis Acid ◽  
Lewis Acids ◽  
The Novel ◽  
X Ray ◽  
Boron Center ◽  
Chloride Methyl

Reaction of 1,8-bis(trimethylstannyl)naphthalene (1) with an excess of BCl3 at –78°, followed by warming to 0°C, results in the exclusive formation of the novel bifunctional Lewis acid 1-(chlorodimethylstannyl)-8-(dichloroboryl)naphthalene (2), a compound in which a boryl and a stannyl moiety coexist at the peri-positions of a naphthalene core. At elevated temperature compound 2 undergoes a chloride–methyl exchange, which affords 1-(dichloromethylstannyl)-8-(chloromethylboryl)naphthalene (3). Compounds 2 and 3 have been characterized by multi-nuclear NMR spectroscopy. The single crystal X-ray analysis for compound 3 reveals a sterically crowded structure with an essentially trigonal planar boron center, and a tin center pentacoordinated in a [4+1]-fashion. Upon exposure to traces of water, compound 3 is converted into the borinic acid derivative 1-(dichloromethylstannyl)-8-(hydroxymethylboryl)naphthalene (4), which has been characterized by multi-nuclear NMR spectroscopy and single crystal X-ray analysis.Key words: multidentate Lewis acids, organoboranes, organostannanes.

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