Benzophenone Crown Ether Acetals with 14- and 17-Membered Rings

The 14-membered ring of 2,2-diphenyl-1,3,6,9,12-pentaoxacyclotetradecane, C₂₁H₂₆O₅, is distorted far from a rectangular structure. By contrast, the homologous 17-membered ring of 2,2-diphenyl-1,3,6,9,12,15-hexaoxacycloheptadecane, C₂₃H₃₀O₆, with an additional oxyethylene unit, adopts an approximately rectangular structure and the cavity has an unsymmetric shape.

-1