Regioselective meta-mercuration followed by Pd-catalysed intramolecular bridging gave birth to a novel type of calixarene bearing a single bond bridge between the meta positions of the neighboring aromatic subunits. These bridged derivatives possess extremely distorted cavities that imply possible amended properties over common calix[4]arenes. This new type of calixarene reactivity can be documented by acid-/electrophile-mediated cleavage of the basic macrocyclic skeleton leading to open oligomeric structures-the behavior of which has never been observed before in classic calix[4]arenes bearing alkoxy groups on the lower rim.

Department of Organic Chemistry University of Chemistry and Technology Prague Technicka 5 166 28 Prague 6 Czech Republic

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Upper rim-bridged calixarenes