Restricted rotation involving the tetrahedral carbon. LX. peri-substituent effect on the rotational barrier of the 9-methyl group in several triptycene derivatives.

G Yamamoto, M Oki

Index: Yamamoto, Gaku; Oki, Michinori Bulletin of the Chemical Society of Japan, 1990 , vol. 63, # 12 p. 3550 - 3559

Full Text: HTML

Citation Number: 12

Abstract

Dynamic 1 H NMR study was made on several 1-substituted 8, 13-dichloro-9- methyltriptycenes and 8-chloro-13-fluoro-9-methyltriptycenes to examine the effect of the peri-substituents on the rotational barrier of the 9-methyl group. The rotational barrier height increases in the expected order as the 1-hydrogen is replaced by a bulkier group up to CH 3, but shows a very low value when a t-butyl group is introduced into 1-position to show ...