Efficient synthesis of a variety of new functionalized oxacalixarenes by Ullmann coupling reactions

Abstract

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, 2006.