ENANTIOPURE TRIOXADECALIN DERIVED LIQUID CRYSTALS: INFLUENCE OF PHENYL SUBSTITUTION ON THE MESOGENIC PROPERTIES

Nickel(0)-catalyzed reaction of pseudo-glucal 1 with Grignard reagents derived from bromobenzene and 1-bromo-4-phenylbenzene gives the corresponding β-C-aryl glycosides 2. Desilylation and hydrogenation of 2 leads to saturated β-C-aryl glycosides 4, which can be used as chiral intermediates in the synthesis of chiral liquid crystals. The combination with p-alkoxy-substituted benzaldehyde leads to compounds 5–6. Alternatively, reaction with p-alkoxy-substituted phenylboronic acids gives the bora analogues 7–9. The mesogenic properties of these compounds are strongly influenced by the presence of an additional phenyl ring in the molecule.