Chirale 2,2′‐Polyoxaalkano‐9,9′‐spirobifluorene

Chiral 2,2′‐polyoxaalkano‐9,9′‐spirobifluorenes From 2,2′‐diacetyl‐9,9′‐spirobifluorene (2), twelve chiral polyethers have been prepared as potential ion‐ and enantiomer‐selective ionophores. The absolute configuration of the polyethers 15–17, 19–22, and 25 has been determined by chemical correlation with vespirenes [11] [29], by circular dichroism, and by X‐ray analysis. The circular dichroism of 15–17, 19 and 21 depends on the size of the macrocycle and indicates that the fluorene chromophores of 19 and 21 with 13‐ and 16‐membered rings respectively deviate considerably from orthogonality.