Abstract
The asymmetric synthesis of a chiral, nonracemic π-conjugated system with D2 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 structure of 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° range. However, CD and UV spectra of 4 in CH2Cl2 are consistent with significant conjugation between the four terphenyl moieties.
Original language | English (US) |
---|---|
Pages (from-to) | 3725-3735 |
Number of pages | 11 |
Journal | Tetrahedron |
Volume | 57 |
Issue number | 17 |
DOIs | |
State | Published - Apr 23 2001 |
Keywords
- Asymmetric synthesis
- Biaryl
- Chiral
- Sparteine
- π-conjugated
ASJC Scopus subject areas
- Biochemistry
- Drug Discovery
- Organic Chemistry