Conformational Analysis and Kinetics of Ring Inversion for Methylene- and Dimethylsilyl-Bridged Dicyclooctatetraene
2001 (English)In: Journal of Organic Chemistry, Vol. 66, no 11, 3871-7 p.Article in journal (Refereed) Published
Dicyclooctatetraenylmethane (1) and dicyclooctatetraenyldimethylsilane (2) in THF-d8 at 272 K exist as mixtures of diastereomers in ratios of 1:0.8 and 1:1, respectively. Nine energy minima (four meso and five racemic conformers) were located for each compound by geometry optimization at the HF/6-31G* level of theory. The effects of torsional strain, steric interactions and dynamic electron correlation were analyzed. The diastereomeric ratios for 1 and 2 were reproduced reasonably well from the total energy calculated for each conformer corrected for its conformational enthalpy and entropy contributions. The ratio of rate constants for bond shift (BS) (kBS(1)/kBS(2)) is three times greater than the corresponding ratio for ring inversion. This suggests that additional substituent effects, such as interactions, are operative in the transition state for BS.
Place, publisher, year, edition, pages
2001. Vol. 66, no 11, 3871-7 p.
IdentifiersURN: urn:nbn:se:umu:diva-9197DOI: doi:10.1021/jo001793aOAI: oai:DiVA.org:umu-9197DiVA: diva2:148868