Confused-Prism[5]arene: a Conformationally Adaptive Host by Stereoselective Opening of the 1,4-Bridged Naphthalene Flap

The confused-prism[5]arene macrocycle (c-PrS[5](Me)) shows conformational adaptive behavior in the presence of ammonium guests. Upon guest inclusion, the 1,4-bridged naphthalene flap reverses its planar chirality from pS to pR (with reference to the pS(pR)(4) enantiomer). Stereoselective directional threading is also observed in the presence of directional axles, in which up/down stereoisomers of homochiral (pR)(5)-c-PrS[5](Me) pseudorotaxanes are formed.