Correlation of acyl ion intensities with product enthalpies from collisionally activated decomposition of molecular ions of small aliphatic ketones

1985 ◽  
Vol 107 (1) ◽  
pp. 115-117 ◽  
Author(s):  
Maurice M. Bursey ◽  
J. Ronald Hass
Keyword(s):  
Molecular Ions ◽  
Aliphatic Ketones

Fragmentations des cétones aliphatiques métastables. II. Compétition entre éliminations de radicaux hydrocarbonés et d'alcanes.

1982 ◽  
Vol 60 (16) ◽  
pp. 2107-2112 ◽  
Author(s):  
Guy Bouchoux ◽  
Yannik Hoppilliard
Keyword(s):  
Molecular Ions ◽  
Low Energy ◽  
Final States ◽  
Energy Channel ◽  
Aliphatic Ketones ◽  
Thermochemical Stability

The fragmentation of the metas table molecular ions of six aliphatic ketones is studied. The ion fragment abundances [M – R•] and [M–RH] (R• being a lateral radical) can be predicted from the thermochemical stability of the corresponding final states. Exceptions to this behavior are found for metastable molecular ions of methylethylketone and methylisopropylketone where it is demonstrated that the lifetime of these ions is too short to permit significant decompositions via the low energy channel after 10−5 s.

The loss of water from molecular ions of aliphatic ketones in electron-impact mass spectra

1969 ◽  
Vol 2 (3) ◽  
pp. 331-333 ◽  
Author(s):  
Adrian N. H. Yeo ◽  
Dudley H. Williams
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Molecular Ions ◽  
Aliphatic Ketones ◽  
Electron Impact Mass ◽  
Impact Mass

Radiation less transitions in gas phase molecular ions

1980 ◽  
Vol 77 ◽  
pp. 705-718 ◽  
Author(s):  
Sydney Leach ◽  
Gérald Dujardin ◽  
Guy Taieb
Keyword(s):  
Gas Phase ◽  
Molecular Ions

THERMAL MODEL FOR THE DESORPTION OF (MOLECULAR) IONS INDUCED BY MeV HEAVY IONS

1989 ◽  
Vol 50 (C2) ◽  
pp. C2-237-C2-243 ◽  
Author(s):  
H. VOIT ◽  
E. NIESCHLER ◽  
B. NEES ◽  
R. SCHMIDT ◽  
CH. SCHOPPMANN ◽  
...  
Keyword(s):  
Heavy Ions ◽  
Thermal Model ◽  
Molecular Ions

Dissociative recombination of molecular ions in noble-gas plasmas

1992 ◽  
Vol 162 (1) ◽  
pp. 35 ◽  
Author(s):  
V.A. Ivanov
Keyword(s):  
Noble Gas ◽  
Dissociative Recombination ◽  
Molecular Ions

Dissociative recombination of electrons and molecular ions

1982 ◽  
Vol 136 (1) ◽  
pp. 25 ◽  
Author(s):  
Aleksandr V. Eletskii ◽  
Boris M. Smirnov
Keyword(s):  
Dissociative Recombination ◽  
Molecular Ions

Gaseous Molecular Ions

1992 ◽  
Author(s):  
Eugen Illenberger ◽  
Jacques Momigny
Keyword(s):  
Molecular Ions

Catalytic Carbonyl-Olefin Metathesis of Aliphatic Ketones: Iron(III) HomoDimers as Lewis Acidic Superelectrophiles

2018 ◽  
Author(s):  
Haley Albright ◽  
Paul S. Riehl ◽  
Christopher C. McAtee ◽  
Jolene P. Reid ◽  
Jacob R. Ludwig ◽  
...  
Keyword(s):  
Lewis Acid ◽  
Olefin Metathesis ◽  
Acid Activation ◽  
Lewis Acid Catalysts ◽  
Distinct Mode ◽  
Aliphatic Ketones ◽  
Carbon Carbon Bond ◽  
Metathesis Reactions ◽  
Acid Catalyzed

<div>Catalytic carbonyl-olefin metathesis reactions have recently been developed as a powerful tool for carbon-carbon bond</div><div>formation. However, currently available synthetic protocols rely exclusively on aryl ketone substrates while the corresponding aliphatic analogs remain elusive. We herein report the development of Lewis acid-catalyzed carbonyl-olefin ring-closing metathesis reactions for aliphatic ketones. Mechanistic investigations are consistent with a distinct mode of activation relying on the in situ formation of a homobimetallic singly-bridged iron(III)-dimer as the active catalytic species. These “superelectrophiles” function as more powerful Lewis acid catalysts that form upon association of individual iron(III)-monomers. While this mode of Lewis acid activation has previously been postulated to exist, it has not yet been applied in a catalytic setting. The insights presented are expected to enable further advancement in Lewis acid catalysis by building upon the activation principle of “superelectrophiles” and broaden the current scope of catalytic carbonyl-olefin metathesis reactions.</div>

Theoretical and experimental studies of palladium-catalyzed site-selective C(sp3)−H bond functionalization enabled by transient ligands

2017 ◽  
Author(s):  
Haibo Ge ◽  
Lei Pan ◽  
Piaoping Tang ◽  
Ke Yang ◽  
Mian Wang ◽  
...  
Keyword(s):  
Bond Activation ◽  
Theoretical Calculations ◽  
Experimental Studies ◽  
Bond Functionalization ◽  
Aliphatic Ketones ◽  
Site Selectivity ◽  
Mechanistic Investigation ◽  
Palladium Catalyzed ◽  
Metal Catalyzed ◽  
Site Selective

Transition metal-catalyzed selective C–H bond functionalization enabled by transient ligands has become an extremely attractive topic due to its economical and greener characteristics. However, catalytic pathways of this reaction process on unactivated sp<sup>3</sup> carbons of reactants have not been well studied yet. Herein, detailed mechanistic investigation on Pd-catalyzed C(sp<sup>3</sup>)–H bond activation with amino acids as transient ligands has been systematically conducted. The theoretical calculations showed that higher angle distortion of C(sp2)-H bond over C(sp3)-H bond and stronger nucleophilicity of benzylic anion over its aromatic counterpart, leading to higher reactivity of corresponding C(sp<sup>3</sup>)–H bonds; the angle strain of the directing rings of key intermediates determines the site-selectivity of aliphatic ketone substrates; replacement of glycine with β-alanine as the transient ligand can decrease the angle tension of the directing rings. Synthetic experiments have confirmed that β-alanine is indeed a more efficient transient ligand for arylation of β-secondary carbons of linear aliphatic ketones than its glycine counterpart.<br><br>

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