The Synthesis and Characterization of New Optically Active ‘dimeric’ ‘pineno’-[4,5]-fused 2,2′-bipyridines linked without spacer or by small spacer groups
✍ Scribed by Nicholas C. Fletcher; F. Richard Keene; Marco Ziegler; Helen Stoeckli-Evans; Heiko Viebrock; Alex von Zelewsky
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- German
- Weight
- 657 KB
- Volume
- 79
- Category
- Article
- ISSN
- 0018-019X
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✦ Synopsis
Abstract
Linked chiral bipyridines 2–4 are prepared by combining two optically active ‘pineno’‐[4,5]‐fused 2,2′‐bipyridines in a stereoselective reaction (Scheme 1). These potential ligands are new members of the ‘chiragen’ family, and are characterized by NMR spectroscopy and, in the case of 2 and 3 by single‐crystal X‐ray analysis. A new synthesis of ‘dipineno’‐[4,5;4′,5′]‐fused 2,2′ ‐bipyridine 8 is described, which, when coupled, gives additional four chiral centres to the analogous ‘chiragen’ series ( → 9). Analysis of the CD spectra allowed conformational information about the solution species to be determined.