Structure‐Reactivity Relationships in Homogeneous Gas‐Phase Reactions: Thermolyses and Rearrangements

Smith, Grant Gill; Kelly, Floyd W.

doi:10.1002/9780470171875.ch2

Cited by 55 publications

(3 citation statements)

References 312 publications

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“…The bicyclic trifluoroacetate 5 , which we have previously used as a probe for concerted elimination, , was therefore solvolyzed in [BMIM][NTf 2 ], where it undergoes facile elimination to give the deuterated alkene 6 exclusively. This stereochemical result is consistent with involvement of cation 7 , which preferentially loses the exo -H. A concerted ester type pyrolytic elimination of trifluoroacetic acid is ruled out since this would be a syn process involving loss of the endo -D . A bimolecular E2 type of elimination would also involve loss of endo -D since a 0° dihedral angle is preferred in bimolecular eliminations in norbornyl systems …”

Section: Resultssupporting

confidence: 74%

Carbocation-Forming Reactions in Ionic Liquids

2005

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A number of trifluoroacetates, mesylates, and triflates have been studied in ionic liquids. Several lines of evidence indicate that all of these substrates react via ionization to give carbocationic intermediates. For example, cumyl trifluoroacetates give mainly the elimination products, but the Hammett rho+ value of -3.74 is consistent with a carbocationic process. The analogous exo-2-phenyl-endo-3-deutero-endo-bicyclo[2.2.1]hept-2-yl trifluoroacetate gives an elimination where loss of the exo-hydrogen occurs from a cationic intermediate. 1-Adamantyl mesylate and 2-adamantyl triflate react to give simple substitution products derived from capture of 1- and 2-adamantyl carbocations by the residual water in the ionic liquid. The triflate derivative of pivaloin, trans-2-phenylcyclopropylcarbinyl mesylate, 2,2-dimethoxycyclobutyl triflate, the mesylate derivative of diethyl (phenylhydroxymethyl)-thiophosphonate, and Z-1-phenyl-5-trimethylsilyl-3-penten-1-yl trifluoroacetate all give products derived carbocation rearrangements (kDelta processes). anti-7-Norbornenyl mesylate gives products with complete retention of configuration, indicative of involvement of the delocalized 7-norbornenyl cation. 1,6-Methano[10]annulen-11-yl triflate reacts in [BMIM][NTf2] to give 1,6-methano[10]annulen-11-ol, along with naphthalene, an oxidized product derived from loss of trifluoromethanesulfinate ion. Analogous loss of CF3SO2- can be seen in reaction of PhCH(CF3)OTf. Ionic liquids are therefore viable solvents for formation of carbocationic intermediates via kC and kDelta processes.

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Section: Resultssupporting

confidence: 74%

Carbocation-Forming Reactions in Ionic Liquids

2005

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“…Topics 1 and 2 are related to each other in that they involve decomposition of a carboxylic acid via either: (i) formation of an alkane (or alkene, alkyne, and arene) and CO 2 (Equation 1); (ii) formation of a ketene and water (Equation 2). In the absence of a metal catalyst, pyrolysis of aliphatic carboxylic acid requires high temperatures (typically >500°C) and is generally non-selective, producing both sets of products (Smith & Kelly, 1971;Brown, 1980;Clark, Nimlos, & Robichaud, 2014).…”

Section: A Background and Scopementioning

confidence: 99%

Organometallic Gas‐phase Ion Chemistry and Catalysis: Insights Into the Use of Metal Catalysts to Promote Selectivity in the Reactions of Carboxylic Acids and Their Derivatives

O’Hair

2020

Mass Spectrometry Reviews

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“…El estudio sobre la pirolisis y la deshidrogenación de haluros de alquilo ha sido estudiado por diversos autores (Maccoll, 1969;Smith et al, 1971;Chuchani, 1995), en ellos se plantea un estado de transición cíclico concertado de cuatro miembros con la formación de su correspondiente olefina, según se muestra en el Esquema 1.…”

Section: Introductionunclassified

Estudio Teórico Y Computacional De La Pirólisis Del 4-Cloro-1-Butanol en Fase Gaseosa Mediante La Teoría Del Funcional De La Densidad

Paz

González

Márquez³

et al. 2022

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Se investigó el mecanismo y la cinética de la pirolisis en fase gaseosa del 4-cloro-1-butanol a nivel DFT. La reacción da como productos tetrahidrofurano, formaldehido, propeno y cloruro de hidrogeno. El mecanismo de eliminación molecular sugiere dos vías de reacción. La primera vía se produce a través de un estado de transición cíclico de cuatro miembros, donde el nivel de teoría WB97XD/6-31G++(d,p) mostró resultados cercanos con los parámetros cinéticos experimentales. La segunda vía ocurre en dos etapas, la primera se da mediante un estado de transición cíclico de cuatro miembros y la segunda con estado de transición cíclico de seis miembros, los niveles de teoría que dieron resultados más cercanos a los experimentales fueron B3LYP/6-31G(d,p) y WB97XD/6-31G++(d,p), para primera y segunda etapa respectivamente. La ruptura del enlace C-Cl, debido a su polarización en el enlace , es el paso determinante de la velocidad en ambas vías de reacción. El análisis topológico NCI se usó para determinar las interacciones no covalentes es todas las estructuras. La variación de la fuerza de los enlaces involucrados en las transiciones se midió mediante el índice IBSI, lo que permitió verificar el mecanismo propuesto

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Structure‐Reactivity Relationships in Homogeneous Gas‐Phase Reactions: Thermolyses and Rearrangements

Cited by 55 publications

References 312 publications

Carbocation-Forming Reactions in Ionic Liquids

Carbocation-Forming Reactions in Ionic Liquids

Organometallic Gas‐phase Ion Chemistry and Catalysis: Insights Into the Use of Metal Catalysts to Promote Selectivity in the Reactions of Carboxylic Acids and Their Derivatives

Estudio Teórico Y Computacional De La Pirólisis Del 4-Cloro-1-Butanol en Fase Gaseosa Mediante La Teoría Del Funcional De La Densidad

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