Synthesis of novel biscrown ethers with rigid cis/trans ethylene bridge

Two novel biscrown ethers with rigid cis/trans ethylene linker were synthesized via Wittig reaction in high yield (about 80%). Their pure cis/trans-isomers were obtained by column chromatography separation. And their structure/configuration was confirmed by 1H NMR, 13C NMR, ESI mass spectrum, elemental analysis and UV-vis spectra.