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Titolo:
A Greek cross dodecaphenylene: sparteine-mediated asymmetric synthesis of chiral D-2-symmetric pi-conjugated tetra-o-phenylenes
Autore:
Rajca, A; Wang, H; Bolshov, P; Rajca, S;
Indirizzi:
Univ Nebraska, Dept Chem, Lincoln, NE 68588 USA Univ Nebraska Lincoln NE USA 68588 aska, Dept Chem, Lincoln, NE 68588 USA
Titolo Testata:
TETRAHEDRON
fascicolo: 17, volume: 57, anno: 2001,
pagine: 3725 - 3735
SICI:
0040-4020(20010423)57:17<3725:AGCDSA>2.0.ZU;2-Y
Fonte:
ISI
Lingua:
ENG
Soggetto:
NONLINEAR-OPTICAL PROPERTIES; INTRAMOLECULAR CARBOLITHIATION; AROMATIC-COMPOUNDS; DERIVATIVES; (-)-SPARTEINE; TETRAPHENYLENE; MOLECULES; LITHIUM; POLYMER; DIMER;
Keywords:
asymmetric synthesis; biaryl; chiral; sparteine; pi-conjugated;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Physical, Chemical & Earth Sciences
Citazioni:
39
Recensione:
Indirizzi per estratti:
Indirizzo: Rajca, A Univ Nebraska, Dept Chem, Lincoln, NE 68588 USA Univ Nebraska Lincoln NE USA 68588 t Chem, Lincoln, NE 68588 USA
Citazione:
A. Rajca et al., "A Greek cross dodecaphenylene: sparteine-mediated asymmetric synthesis of chiral D-2-symmetric pi-conjugated tetra-o-phenylenes", TETRAHEDRON, 57(17), 2001, pp. 3725-3735

Abstract

The asymmetric synthesis of a chiral, nonracemic pi -conjugated system with D-2 point group of symmetry, dodecaphenylene 4 is described. In the key step, (-)-sparteine- and Cu(II)-mediated oxidation of 2,2'-dilithio-1,1'-biaryls in ether gives the corresponding dimers, tetra-o-phenylenes, in 80% isolated yields and 50-60% ee's. X-Ray crystallography confirms the structureof rac-4 and its molecular shape of a Greek cross. The torsional angles between the benzene rings in the tetra-o-phenylene core of rac-4 are in the 56.5-71.0 degrees range. However, CD and UV spectra of 4 in CH2Cl2 are consistent with significant conjugation between the four terphenyl moieties. (C)2001 Elsevier Science Ltd. All rights reserved.

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Documento generato il 23/01/20 alle ore 12:17:12