Efficient Synthesis of a Variety of New Functionalized Oxacalixarenes by Ullmann Coupling Reactions

We have developed an efficient method to synthesize a new type of oxacalix[4]arenes containing nitrogen functional groups in a single step, through N,N‐dimethylglycine‐promoted Ullmann coupling reactions starting from aryl dibromides in yields of up to 37 %. With a aryl difluoride as substrate, a large, fully aromatic crown ether 8 could be obtained in 25 % yield. Further functionalization of the nitrogen functional groups in the cores of these oxacalixarenes may offer new opportunities for constructing desirable molecular architectures and a range of nitrogen‐based multidentate ligands. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)