ISSN:
0192-8651
Keywords:
three-membered ring formation
;
intramolecular nucleophilic substitution
;
ab initio molecular orbital method
;
Chemistry
;
Theoretical, Physical and Computational Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Computer Science
Notes:
Three-membered ring (3MR) forming processes of -X(SINGLE BOND)CH2(SINGLE BOND)CH2(SINGLE BOND)F and -CH2(SINGLE BOND)C((SINGLE BOND)Y)(SINGLE BOND)CH2(SINGLE BOND)F (X(DOUBLE BOND)CH2, O, or S and Y(DOUBLE BOND)0 or S) through a gas phase neighboring group mechanism (SNi) are studied theoretically using the ab initio molecular orbital method with the 6-31+G* basis set. When electron correlation effects are considered, the activation (ΔG≠) and reaction energies (ΔG0) are lowered by ca. 10 kcal mol-1, indicating the importance of the electron correlation effect in these reactions. The contribution of entropy of activation (-TΔS≠) at 298 K to ΔG≠ is very small, and the reactions are enthalpy controlled. The ΔG≠ and ΔG0 values for these ring closure processes largely depend on the stabilities of the reactants and the heteroatom acting as a nucleophilic center. The Bell-Evans-Polanyi principle applies well to all these reaction series. © 1997 John Wiley & Sons, Inc. J Comput Chem 18: 1773-1784, 1997
Additional Material:
6 Ill.
Type of Medium:
Electronic Resource
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