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Synthesis, X‐ray Structural Analysis, and Conformational Study of anti ‐[3.3]Metacyclophane Quinhydrone Dimethyl Ether
Author(s) -
Shinmyozu Teruo,
Wen Gang,
Hirakawa Takafumi,
Osada Satoshi,
Takemura Hiroyuki,
Sako Katsuya,
Rudziński Jerzy M.
Publication year - 1996
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199619960209
Subject(s) - chemistry , isomerization , quinhydrone electrode , ether , dimethyl ether , stereochemistry , computational chemistry , crystallography , organic chemistry , working electrode , methanol , electrolyte , catalysis , electrode
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.