Abstract A new C 3v-symmetrical calix [6] azacryptand, that is, calix [6] tmpa (11), was synthesized by efficient [1+ 1] macrocyclization reactions. Remarkably, both linear and convergent synthetic strategies that were applied lead to equally good overall yields. Calix [6] tmpa behaves as a single proton sponge and appeared reluctant to undergo polyprotonation, unlike classical tris (2-pyridylmethyl) amine (tmpa) derivatives. It also acts ...
