scholarly journals Huisgen's 1,3‐Dipolar Cycloadditions to Fulvenes Proceed via Ambimodal [6+4]/[4+2] Transition States

2020 ◽  
Vol 132 (30) ◽  
pp. 12512-12516
Author(s):  
Fang Liu ◽  
Yu Chen ◽  
K. N. Houk
Keyword(s):  
Transition States ◽  
Dipolar Cycloadditions

Ab Initio Study of Solvent Effects on Rate of 1,3-Dipolar Cycloadditions of Benzonitrile Oxide and Various Dipolarophiles

2003 ◽  
Vol 2003 (2) ◽  
pp. 91-95 ◽  
Author(s):  
E. Rajaeian ◽  
M. Monajjemi ◽  
M.R. Gholami
Keyword(s):  
Hydrogen Bonding ◽  
Oxygen Atom ◽  
Water Molecule ◽  
Ab Initio ◽  
Solvent Effects ◽  
Transition States ◽  
Molecular Orbital Calculations ◽  
Interaction Energies ◽  
Ab Initio Study ◽  
Dipolar Cycloadditions

Ab initio molecular orbital calculations have been used to investigate the structures and the transition states of 1,3-dipolar cycloadditions between benzonitrile oxide with ethylene, cyclopentene, acrylonitrile and tetracyanoethylene in heptane and water: calculations reveal enhanced hydrogen bonding of a water molecule to the transition states for the cycloaddition 1,3-dipolar of reaction of benzonitrile oxide with cyclopentene, the optimal interaction energies being 0.7 kcal/mol more favourable for hydrogen bonding to the oxygen atom in the transition states than for the reactants.

scholarly journals Ab Initio Calculation of Thermodynamic and Kinetic Quantities for 1,3-Dipolar Cycloadditions of Benzonitrile Oxide with Various Dipolarophiles

2002 ◽  
Vol 2002 (6) ◽  
pp. 279-281 ◽  
Author(s):  
E. Rajaian ◽  
M. Monajjemi ◽  
M.R. Gholami
Keyword(s):  
Ab Initio ◽  
Molecular Orbital ◽  
Rate Constant ◽  
Thermodynamic Stability ◽  
Ab Initio Calculation ◽  
Transition States ◽  
Molecular Orbital Calculations ◽  
Free Energies ◽  
Energy Calculations ◽  
Dipolar Cycloadditions

Ab initio molecular orbital calculations have been used to investigate the structures and transition states of 1,3-dipolar cycloadditions between benzonitrile oxide with ethylene, acrylonitrile, tetracyanoethylene and cyclopentene. Geometry optimisations and energy calculations were performed with RHF/6–31G*//RHF/6–31G* in each case. Calculation of vibrational frequencies permitted computation of the enthalpies, Gibbs free energies and rate constant of reactions. Cycloadditions of 1,3-dipolar benzonitrile oxide with electron-poor dipolarophiles have higher rates and lower thermodynamic stability than with other dipolarophiles.

Theoretical Computations on the Pyrolysis of Alkyl (dithio)acetates

2020 ◽  
Vol 17 (3) ◽  
pp. 224-233
Author(s):  
Xun Zhu ◽  
Chen Jian ◽  
Xiuqin Zhou ◽  
Abdullah M. Asiri ◽  
Khalid A. Alamry ◽  
...  
Keyword(s):  
Transition States ◽  
Membered Ring ◽  
Pyrolysis Process ◽  
Alkyl Esters ◽  
Charge Distributions ◽  
Theoretical Analyses

The pyrolysis of methyl alkyl esters I to III and dithioesters IV to VI were theoretically calculated. All possible pyrolysis paths were considered. Both esters and dithioesters presented three potential paths via six-, four- and five-membered ring transition states, respectively. The calculation processes were calculated using MP2/6-31G(d) set. In-depth theoretical analyses were also presented, including NBO related analyses, synchronicities, and charge distributions, to reveal the detailed pyrolysis process.

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