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Synthesis, X-ray Structural Analysis, and Conformational Study of anti-[3.3]Metacyclophane Quinhydrone Dimethyl Ether

✍ Scribed by Shinmyozu, Teruo ;Wen, Gang ;Hirakawa, Takafumi ;Osada, Satoshi ;Takemura, Hiroyuki ;Sako, Katsuya ;Rudziński, Jerzy M.

Publisher
John Wiley and Sons
Year
2006
Tongue
English
Weight
578 KB
Volume
1996
Category
Article
ISSN
0947-3440

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✦ Synopsis

Abstract

Synthesis and X‐ray structural analysis of anti‐[3.3]metacyclophane‐2,11‐dione quinhydrone dimethyl ether (3) are described. The formation of anti‐3 starting from syn‐9 may be ascribed to the syn→anti isomerization of the syn‐quinhydrone 17 according to a benzoquinone ring inversion process. This is in contrast to a reverse anti→syn isomerization (4 → 5a) of anti‐[3.3]metacyclophane quinhydrone dimethyl ether 4. Results of a conformational analysis of the parent [3.3]metacyclophanes (1 and 2) and the calculated relative stability of syn and anti isomers (3, 17 and 4, 5a) suggest that the major driving force of these syn‐anti isomerizations originates from the relative thermodynamical stability of the syn and anti isomers rather than from the donor‐acceptor interaction between the rings. The anti geometry of 3 was confirmed by an X‐ray structural analysis.

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