Nucleophilic attacks on carbon–carbon double bonds. Part XIII. Vinylic substitution of 1,1-dicyano-2-p-dimethylaminophenyl-2-halogenoethylenes by aromatic amines in acetonitrile

“…The rate-determining step varied from the departure of the leaving group (3, to proton transfer (6,8), to the nucleophilic attack on the olefin (7). Rappoport et al (9,10) have studied the attack of primary amines on 1 , l -dicyano-2-fluoroolefins, in which the fluorine is replaced to yield a cyanoenamine. The reaction was shown to be base catalysed and a mechanism involving a competition between carbon-fluorine bond cleavage and nitrogen-hydrogen bond cleavage was proposed.…”

Section: Resultsmentioning

confidence: 99%

“…The results show that the reaction is catalysed by tertiary amines, oxalate and acetate ions, but not by alkyl ammonium ions, perchlorate or chloride ions. Rappoport and Ta-Shma (9) also found that the ammonium ion did not catalyse the reaction of p-toluidine with 1,l-dicyano-2-p-dimethylaminophenyl-2-…”

Section: Kineticsmentioning

confidence: 99%

Nucleophilic attack on the carbon–carbon double bond. I. Reaction of primary and secondary amines with 2,2-di(4-nitrophenyl)-1,1-difluoroethene

Leffek¹,

Maciejewska²

1986

Can. J. Chem.

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KENNETH T. LEFFEK and URSZULA MACIEJEWSKA. Can. J . Chem. 64, 2274Chem. 64, (1986. The reaction of primary and secondary amines with 2,2-di(4-nitropheny1)-1,l-difluoroethene (1) in acetonitrile solvent gives first 2,2-di(4-nitropheny1)-1-fluoro-1-aminoethene (2) and then 2,2-di(4-nitropheny1)-1,l-difluoro-l-aminoethane (3). With excess amine, pseudo-first-order rate constants for the production of 2 were measured, which showed a second-order reaction, together with a catalysed third-order reaction. In addition to the reagent amines, the reaction is also catalysed by tertiary amines and bases such as oxalate and acetate, but not by chloride and perchlorate, nor by ammonium ions. The enthalpy of activation for the reaction of piperidine with 1 in acetonitrile is 3.7 kcal mol-I. but for the catalysed reaction an apparent value of -2.2 kcal mol-' was obtained. It is concluded that the reaction proceeds via a pre-equilibrium to a zwitterion, followed by another equilibrium giving a carbanion that yields the product (2) by a rate-determining cleavage of the carbon-fluorine bond.KENNETH T. LEFFEK et URSZULA MACIEJEWSKA. Can. J. Chem. 64, 2274Chem. 64, (1986. Lorsqu'on opere dans 1'acCtonitrile comme solvant, la rCaction des amines primaires ainsi que secondaires avec le di (nitro-4 phCny1)-2,2 difluoro-l , l Cthene (1) conduit initialement a la formation du di (nitro-4 phCny1)-2,2 fluoro-1 amino-l Cthene (2) et finalement au di (nitro-4 phCny1)-2.2 difluoro-1,1 amino-l Cthane (3). OpCrant en prCsence d'un exc.5~ d'amine, on a mesurC les constantes de vitesse du premier ordre pour la formation du compost? 2; on a aussi not6 la prksence d'une reaction du deuxieme ordre ainsi qu'une rCaction catalyste du troisieme ordre. En plus des rCactifs aminis, les amines tertiaires et les bases comme l'oxalate et 1'acCtate catalysent aussi cette rCaction: toutefois-les ions chlorure, perchlorate ainsi qu'arnmonium n'agissent pas comme catalyseurs. Dans I'acCtonitrile, l'enthalpie d'activation pour la reaction du composC 1 avec la pipCridine est Cgale a 3,7 kcal mol-I; toutefois, pour la reaction catalysCe, on observe une valeur apparente de -2,2 kcal m o l ' . On en conclut que la rCaction se produit par le biais d'un prt-Cquilibre conduisant 21 un zwitterion qui, par un autre kquilibre, conduit a un carbanion qui conduit au produit 2 par un clivage de la liaison carbone-fluor qui dCtermine la vitesse de la rCaction.[Traduit par la revue]

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“…Such a composite acceptor is (1,3‐dioxo‐2,3‐dihydro‐1 H ‐inden‐2‐ylidene)propanedinitrile 1 , also referred to as 2‐(dicyanomethylene‐1,3‐indanedione); CNIND may be considered to be analogous to ethenetetracarbonitrile 2 (TCNE) in its reactions. Like the latter, it readily adds N ‐nucleophiles such as secondary aliphatic and primary aromatic amines at the dicyanomethylene carbon atom with release of hydrogen cyanide, analogous to the corresponding reaction of 2 . Tertiary aromatic amines (such as N , N ‐dimethylaniline) are prone to attack with their p ‐carbon atom, followed by release of HCN .…”

Section: Introductionmentioning

confidence: 99%

Recent Heterocyclic Compounds from (1,3‐Dioxo‐2,3‐dihydro‐1H‐inden‐2‐ylidene)propanedinitrile

Hassan

Mostafa

2014

Journal of Heterocyclic Chem

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Nucleophilic attacks on carbon–carbon double bonds. Part XIII. Vinylic substitution of 1,1-dicyano-2-p-dimethylaminophenyl-2-halogenoethylenes by aromatic amines in acetonitrile

Abstract: While the adduct (IV) may be formed by an inter-or intramolecular proton transfer t o (V), its inclusion in the reaction scheme adds very little t o the understanding of the reaction, but complicates the kinetic scheme.

Cited by 15 publications

References 1 publication

The importance of hyperconjugation in nucleophilic vinylic substitution

The importance of hyperconjugation in nucleophilic vinylic substitution

Nucleophilic attack on the carbon–carbon double bond. I. Reaction of primary and secondary amines with 2,2-di(4-nitrophenyl)-1,1-difluoroethene

Recent Heterocyclic Compounds from (1,3‐Dioxo‐2,3‐dihydro‐1H‐inden‐2‐ylidene)propanedinitrile

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