A comparative study of the stereochemistry of 4-acetyl-, formyl- and carboxy-benzo-9-crown-3 ether via X-ray crystallography and solid state and solution NMR spectroscopy

Abstract The X-ray crystal structures for the title molecules show remarkably similar geometries in the crown ether regions compared to benzo-9-crown-3 ether itself. Solid phase 13 C NMR chemical shift differences of ca. 8.5 ppm are observed between the two aryl–O–C ∗ carbons and are explained using results of ab initio calculations previously performed on anisole. Chemical shift assignments have been verified by the use of selectively deuterated derivatives.