Details

Autor(en) / Beteiligte

• Montoya-Pelaez, Pedro J
• Uh, Yoon-Seo
• Lata, Christopher
• Thompson, Matthew P
• Lemieux, Robert P
• Crudden, Cathleen M

Titel

The Synthesis and Resolution of 2,2‘-, 4,4‘-, and 6,6‘-Substituted Chiral Biphenyl Derivatives for Application in the Preparation of Chiral Materials

Ist Teil von

• Journal of organic chemistry, 2006-08, Vol.71 (16), p.5921-5929

Ort / Verlag

Washington, DC: American Chemical Society

Erscheinungsjahr

2006

Quelle

MEDLINE

Beschreibungen/Notizen

• Various routes were examined for the synthesis of chiral biphenyl species that are substituted at the 2,2‘, 4,4‘ and 6,6‘ positions. Because the biaryl bond is tetrasubstituted, many coupling reactions were not suitable. The most reliable coupling reaction proved to be the Ullmann, which gave the desired product in 82% yield. The products were required as the starting point for the preparation of chiral materials using these as the monomer. For this reason, a route was required that produced large quantities of both enantiomers. The two enantiomers were resolved at the penultimate step by the use of chiral HPLC. A complicating feature proved to be the necessity to have a reactive group at the 4,4‘ positions, which would permit polymerization though this point. Ultimately, we employed an Ullmann coupling on a dibrominated arene, which occurred selectively at the more hindered bromine by virtue of the directing effect of an ortho ester substituent.