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Stereoselective Synthesis and Physicochemical Properties of Liquid-Crystal Compounds Possessing a trans-2,5-Disubstituted Tetrahydropyran Ring with Negative Dielectric Anisotropy.

Authors :
Araki, Keisuke
Yamamoto, Tetsuya
Tanaka, Ryoji
Tanaka, Saori
Ushioda, Makoto
Gotoh, Yasuyuki
Yamakawa, Tetsu
Inoue, Munenori
Source :
Chemistry - A European Journal. Feb2015, Vol. 21 Issue 6, p2458-2466. 9p.
Publication Year :
2015

Abstract

Three stereoselective syntheses and the physicochemical properties of trans, trans-5-(4-ethoxy-2,3-difluorophenyl)-2-(4-propylcyclohexyl)tetrahydropyran, which is an important liquid-crystal compound with a large negative dielectric anisotropy (Δ ε=−7.3), are described. The key step in the construction of the trans-2,5-disubstituted tetrahydropyran ring in the first approach involved a benzylic cation mediated intramolecular olefin cyclization of a 2-allyloxy-1-arylethanol derivative. The second method included the Et2Zn-induced 1,2-aryl shift of a bromohydrin obtained from a hetero-Diels-Alder reaction, followed by stereoselective bromination. The third approach utilized the hetero-Diels-Alder reaction of trans-4-propylcyclohexanecarboxaldehyde and a 2-aryl-3-(trimethylsilyl)oxy-1,3-butadiene, followed by stereoselective protonation. From results obtained by using a quantum chemical calculation method, the reason why the target compound shows a large negative Δ ε value is discussed. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
09476539
Volume :
21
Issue :
6
Database :
Academic Search Index
Journal :
Chemistry - A European Journal
Publication Type :
Academic Journal
Accession number :
100632848
Full Text :
https://doi.org/10.1002/chem.201405495