Synthesis and Reactivity of Functionalized Bridged <i>m</i>-Xylylenedioxycalix[6]arenes

The synthesis of A,D-m-xylylene-bridged calix[6]arenes 1−8 functionalized at position 5 of the spacer arm is described. The cone conformation of the new bridged calix[6]arenes has been established by 1H and 13C NMR. The X-ray structure of compound 6 confirmed the cone conformation also in the solid state. Compounds 9 and 10, which are branched-like structures, were obtained by reductive amination of 5-amino-A,D-m-xylylene-bridged-B,C,E,F-tetra-O-ethylcalix[6]arene 7 with diformyl calix[4]arene and CTV derivatives 22 and 24, respectively.