Conformational Study of <i>N</i>,<i>N</i>′‑Diacyl Bispidines and Dioxo Bis-bispidines: Planar Chirality and Molecular Switching

N,N′-Diacyl bispidines exhibit chirality in the absence of a chiral center and axis. Conformational analysis indicates planar chirality in the molecular structure as a result of open-ended chiral planes, which has been confirmed by X-ray diffraction studies. Substantial chiral–achiral molecular switching is observed in di­(haloacetyl) bispidines upon changing the solvent polarity. Tethering the chiral planes with a bispidine linker alters the planar chirality significantly and renders the resulting bis-bispidine macrocycles achiral.