Catalytic Ability of Flexible Octopus-Type Calixarene in Ester-Forming Reactions and Its Structural Properties

Article abstract of DOI:10.1021/jo00069a039

The ester-forming reaction of alkali metal carboxylates with alkyl halides was catalyzed by the octopus-type calix<6>arene 1 which bears six 3,6,9-trioxadecyl substituents at the phenolic oxygens.The catalytic ability of 1 was significantly large in CH2Cl2 and CH3CN but negligible in less polar solvents such as benzene and dioxane.The catalytic ability is also affected by the amount of water present in the reaction system.A similar solvent effect was found in the alkali metal cation extraction by 1 from aqueous solutions to organic solvents.The conformation and structural mobility of 1 in organic solvents were studied by (1)H NMR spectroscopy at varying temperatures.Compound 1 had a 1,4-anti conformation (see Figure 4) both in CD2Cl2 and C6D6, but the orientation of the substituents on the aromatic rings of 1 varied with temperature.The reactivity features of 1 are discussed on the basis of its structural properties.