INDO calculations on the sigmatropic [1, 5] H-Shift in 1,3-cyclohexadiene and 1,3,5-cycloheptatriene A homo-cyclopentadienyl transition state model

Dobbelaere, JR Jan de; Zeeventer, EL Erica van; Haan, JW Jan de; Buck, HM Henk

doi:10.1007/bf01125902

Cited by 13 publications

(18 citation statements)

References 9 publications

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“…The distance between the carbon atoms involved in the hydrogen transfer of TS2 is predicted to be 2.52 Å by all three levels of theory employed. This value is within the 2.5−2.6 Å range noted by Houk and co-workers 34 but is considerably greater than the INDO prediction of 2.31 Å …”

Section: Resultssupporting

confidence: 71%

“…Including ΔZPVEs, the B3LYP/6-31G* model gives a value of 37.2 kcal/mol for the reaction barrier that is in reasonable accord with the experimental value of 31−32 kcal/mol, but still somewhat too large. The agreement between experiment and the INDO-calculated reaction barrier for TS2 must be regarded as fortuitous, particularly in light of the apparent failings of INDO at computing geometries (the C4−C7 distance of TS2 is 0.2 Å shorter than the B3LYP value) and the ground state energies of CHT . Also noteworthy is the superficial structural similarity of TS1 to the transition structure of the [1,5] sigmatropic hydrogen shift in cyclopentadiene .…”

Section: Discussionmentioning

confidence: 89%

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Molecular Orbital Studies of Methoxy-1,3,5-cycloheptatriene Isomers: Results from Semiempirical, ab Initio, and Density Functional Theory Calculations

Donovan

White

1996

J. Org. Chem.

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The fully optimized structures and relative energies of all possible methoxy-1,3,5-cycloheptatriene (MCHT) isomers have been determined by semiempirical, ab initio, and density functional theory (DFT) molecular orbital calculations. All methods identify the boat conformation of 1-methoxy-1,3,5-cycloheptatriene as the most stable species in this group of compounds. In order to evaluate boat interconversion barriers, optimizations of the planar isomers were also performed. For comparison purposes, we applied the same computational methodologies to boat and planar conformations of 1,3,5-cycloheptatriene (CHT). Among the semiempirical methods, the SAM1 approximation was found to best reproduce the ab initio and DFT results. Examination of rotational energy profiles allowed for identification of the factors controlling the preferred orientations of the methoxy group in these compounds. The calculations predict that methoxy substitution has little influence on the preferred conformation of the seven-membered ring and only a minor impact on the energy required for interconversion of boat conformations through a planar transition structure. Inclusion of electron correlation makes little difference on the calculated relative energies of the MCHT isomers and optimized geometries but significantly improves the computed reaction barriers involved in the CHT hydrogen transfer transition structures.

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Section: Resultssupporting

confidence: 71%

Section: Discussionmentioning

confidence: 89%

Molecular Orbital Studies of Methoxy-1,3,5-cycloheptatriene Isomers: Results from Semiempirical, ab Initio, and Density Functional Theory Calculations

Donovan

White

1996

J. Org. Chem.

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“…All calculations were performed using Gaussian 98W (INDO calculations have been reported for 1,3‐cyclohexadiene; 15). The density functional method was employed using Becke's three‐parameter hybrid method 16 with the Lee–Yang–Parr correlation function 17 and the 6‐31G* basis set 18.…”

Section: Methodsmentioning

confidence: 99%

1,5‐hydrogen shifts in methyl‐1,3‐cycloheptadienes

Hess

2002

Int J of Quantum Chemistry

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“…Scheme 1. there are three options: electrocyclic ring-opening to give 1,2divinylbenzene (12) and two 1,5-H shifts, viz. from C(2) to C(4) and from C(3) to C(1), both leading back to (10).…”

Section: Methodsmentioning

confidence: 99%

Thermolysis of phenyl-substituted 1,2-dihydronaphthalenes. Evidence for diphenylbutadienes as intermediates

Lamberts¹,

CUPPEN²,

Laarhoven³

1985

J. Chem. Soc., Perkin Trans. 1

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~~The thermal rearrangements of the four phenyl-substituted I ,2-dihydronaphthalenes (1 5), (16), (19), and (20) have been studied by flash vacuum pyrolysis (FVP).By using the deuteriated starting compounds [3,4-2H2] -(1 5) and [3,4-2H2] -(1 6), it has been established that 1and 4-phenyl-I ,2-dihydronaphthalene (1 5) and (19) and 2-and 3-phenyl-I ,2dihydronaphthalene (1 6) and (20) are interconverted via the intermediates 1and 2-phenyl-2,3dihydronaphthalene (1 7) and (1 8), respectively, through two consecutive, sigmatropic 1,5hydrogen shifts. In both processes partial oxidation to the corresponding phenylnaphthalenes (21 ) and (22) takes place. The deuterium distribution in the pyrolysis products suggests that in the hot zone diphenylbutadienes are formed, which are reconverted into phenyldihydronaphthalenes upon reaching the cold receiving flask. By FVP of 4-(p-tolyl)-l,2-dihydronaphthalene (34), 1 -phenyl-I -( ptolyl) butadiene (39), and 1 -phenyl-4-(p-tolyl) butadiene (45) the latter type of interconversion could J. Chem. SOC. B, 1969, 523. Table2. Coupling constants (Hz) of the non-aromatic protons in DHN and the PDHNs. Compound (15), (16), and (20) in CDCI,; (19) and (10) in CCI, Compound J 1 , J1.2 J *

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INDO calculations on the sigmatropic [1, 5] H-Shift in 1,3-cyclohexadiene and 1,3,5-cycloheptatriene A homo-cyclopentadienyl transition state model

Cited by 13 publications

References 9 publications

Molecular Orbital Studies of Methoxy-1,3,5-cycloheptatriene Isomers: Results from Semiempirical, ab Initio, and Density Functional Theory Calculations

Molecular Orbital Studies of Methoxy-1,3,5-cycloheptatriene Isomers: Results from Semiempirical, ab Initio, and Density Functional Theory Calculations

1,5‐hydrogen shifts in methyl‐1,3‐cycloheptadienes

Thermolysis of phenyl-substituted 1,2-dihydronaphthalenes. Evidence for diphenylbutadienes as intermediates

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