Molecular Waterwheel (Noria) from a Simple Condensation of Resorcinol and an Alkanedial

A wheel surprise: Reaction of resorcinol and 1,5-pentanedial in ethanol at 80 °C for 48 h in the presence of HCl surprisingly afforded a soluble cyclic oligomer in high yield (83 %) under thermodynamic control. Single-crystal X-ray analysis revealed a waterwheel-like structure with a large hydrophobic hole through the center (see picture). A carboxylic ester derivative of the compound was shown to be highly selective for Rb+ ions. Supporting information for this article is available on the WWW under http://www.wiley-vch.de/contents/jc_2002/2006/z603013_s.pdf or from the author. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.