عنوان

Cycloaddition reactions of a heterocyclic nitrone

TLpq230749044

انگلیسی

Cycloaddition reactions of a heterocyclic nitrone

[Thesis]

H. A. S. Al-Muallem

King Fahd University of Petroleum and Minerals (Saudi Arabia)

1992

180

M.S.

King Fahd University of Petroleum and Minerals (Saudi Arabia)

1992

A study of the regiochemical and stereochemical behavior of the addition reaction of a heterocyclic nitrone, 5,6-dihydro-1,4-oxazine 4-oxide with a series of alkenes has been carried out. The high degree of regiochemical control in these concerted reactions has been explained in terms of frontier molecular orbital treatment. Rate constants for the cycloaddition of the heterocyclic nitrone with several alkenes have been determined at 36C by H NMR spectroscopy. Differences in the rates of cycloadditions have been explained in terms of combination of various factors. The barrier to nitrogen inversion in the nitrone cycloaddition products has been determined by detailed band shape analysis of proton and carbon NMR spectra. The chair inversion has been slowed, in one case to show the presence of the two forms of the cis isomers. The major conformational isomer is shown to be the cis conformer, which is in equilibrium with the minor trans conformer. A mechanistic study of peracid induced ring opening of several cycloadducts has been carried out. (Abstract shortened by UMI.)

Chemistry

Chemistry

Organic chemistry

Pure sciences

H. A. S. Al-Muallem

p

[Thesis]

276903

a

Y