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 ...
[Bryant, Judi A.; Helgeson, Roger C.; Knobler, Carolyn B.; deGrandpre, Mark P.; Cram, Donald J. Journal of Organic Chemistry, 1990 , vol. 55, # 15 p. 4622 - 4634]