ISSN:
0020-7608
Keywords:
Computational Chemistry and Molecular Modeling
;
Atomic, Molecular and Optical Physics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Ab initio molecular-orbital theory with the STO-3G and 4-31 G basis sets has been used to study the 1,3-sigmatropic hydrogen rearrangements: propene→propene, formic acid→formic acid, and vinyl alcohol→acetaldehyde, and the1,5-shifts:1,3-pentadiene→ 1,3-pentadiene and β-hydroxyacrolein→ β-hydroxyacrolein. Transition states have been determined using gradient procedures. Improved descriptions of the energies of the reactions have been obtained using 3 × 3 configuration interaction. In accord with expectations based on orbital-symmetry considerations, the calculated barriers are considerably greater for 1,3- than for 1,5-shifts. The forbidden pathway for the degenerate 1,3-shift in propene is predicted to require less activation energy than the allowed pathway, a result that can be rationalized in terms of interactions with subjacent and superjacent orbitals.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/qua.560140609
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