Restricted Rotation Involving the Tetrahedral Carbon. XLIV. Atropisomers of 2, 3-Dichloro-9-(1-hydroxy-1-methylethyl) triptycene and Related Compounds

…, Y Tanaka, G Yamamoto, N Nakamura

Index: Oki, Michinori; Tanaka, Yoshiyuki; Yamamoto, Gaku; Nakamura, Nobuo Bulletin of the Chemical Society of Japan, 1983 , vol. 56, # 1 p. 302 - 305

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Citation Number: 13

Abstract

Atropisomers of 2, 3-dichloro-9-(1-hydroxy-1-methylethyl) triptycene were obtained as stable compounds at room temperature. The barrier to rotation (±sc→ ap) was 34.0 kcal/mol at 153° C. Other 9-(1-hydroxy-1-methylethyl) triptycenes carrying a substituent in the 1-position of the skeleton gave±sc isomers only. Attempted isomerization of the±sc forms failed because the free energy difference between the±sc and ap forms is great due to the steric ...