Synthese und Eigenschaften kalamitischer Flüssigkristalle aus desoxygenierten Kohlenhydrat‐Derivaten

Synthesis and Properties of Calamitic Liquid Crystals from Deoxygenated Carbohydrate Derivatives Treatment of the L‐arabino‐ and Llyxo‐configurated glycals 1 and 7 with trimethylsily cyanide leads to the formation of the anomeric nitriles 2, 3 and 15, 17, respectively. The configurational assignments are based on hydrogenated products such as 6 or 8 and 10. Depending on the configurations of the olefinic nitril sugars, various hydrogenation results are observed using palladium/charcoal or the Wilkinson catalyst. Methanolysis provides the corresponding methyl esters. The preparation of liquid‐crystalline derivatives follows the classical route. In comparing the properties of these saccharide‐based liquid crystals with the corresponding cyclohexane derivatives, the dominant influence of the anomeric effect on the tendency for phase formation can be observed. Some of the novel derivatives show highly twisted cholesteric and wide blue phases.