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8,14,30,36‐Tetramethoxy[2.0.2.0](1,6)naphthalenophane‐1,19‐diyne: A Double‐Helically Twisted Cyclophane by Diastereoselective Dimerization
Author(s) -
Kawase Takeshi,
Nakamura Takamitsu,
Utsumi Keiichiro,
Matsumoto Kouzou,
Kurata Hiroyuki,
Oda Masaji
Publication year - 2008
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.200700274
Subject(s) - monoclinic crystal system , bathochromic shift , chemistry , crystallography , molecule , stereochemistry , toluene , yield (engineering) , coupling reaction , crystal structure , proton nmr , materials science , organic chemistry , fluorescence , catalysis , physics , quantum mechanics , metallurgy
The title compound and its corresponding etheno‐ and ethano‐bridged compounds were successfully synthesized in enantiomerically pure form by McMurry coupling of 2,2′‐dimethoxy‐( R )‐ or ‐( S )‐1,1′‐binaphthyl‐6,6′‐dicarbaldehydes as the key reaction. The reaction proceeded in a highly diastereoselective manner; the reaction of the racemic dialdehyde did not afford the meso coupling product but gave only the racemic one in poor yield. The diyne crystallized in the chiral monoclinic space group P 2 1 from toluene/hexane. Structural analysis reveals that it has a considerably twisted double‐helical structure in crystal form. The spectral properties (NMR, UV/Vis, and CD) clearly indicate the highly strained nature of the molecule. In particular, its UV/Vis and CD spectra exhibit a bathochromic shift of about 20 nm for the naphthyl π–π* transitions.