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Absolute control of helical handedness in quinoline oligoamides
Amol M Kendhale1, Legiso Poniman, Zeyuan Dong
1Institut Européen de Chimie et Biologie, Université de Bordeaux-CNRS UMR 5248 and UMS 3033, 2 rue Robert Escarpit, F-33607 Pessac, France.
Abstract:
The synthesis of quinoline-derived helically folded aromatic oligoamides functionalized by various chiral functions at their N-terminus is reported. When a (1S)-(-)-camphanyl moiety was introduced, it was found that helix handedness was completely shifted to right-handed helicity (de > 99%), in both protic and nonprotic solvents. The absolute helical sense and the de values were unambiguously characterized by using (1)H NMR, circular dichroism (CD), and X-ray crystallography. The crystal structure of these compounds allowed us to propose a rationale for the efficiency of helix handedness induction based on a combination of steric factors and intramolecular hydrogen bonding.
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