Effects of para-Substituents on the Rates of Inversion of Biphenyl Derivatives. I. 5, 7-Dihydrodibenzo [c, e] thiepins

M Oki, H Iwamura, G Yamamoto

Index: Oki,M. et al. Bulletin of the Chemical Society of Japan, 1971 , vol. 44, p. 262 - 265

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Citation Number: 17

Abstract

Several 3, 9-disubstituted 5, 7-dihydrodibenzo [c, e] thiepins were synthesized and temperature dependence of their NMR spectra was examined. All the substituted derivatives showed a lower energy barrier to inversion than the unsubstituted one. The effects of the substituents on the energy barrier may be interpreted in terms of resonance stabilization and/or out-of-plane bending of the axis bond at the transition state.