Coupling of 4-(chloromethyl)benzoyl chloride (I) with 2-(trimethylsilyl)ethanol, followed by displacement of the benzylic chloride with NaI in acetone leads to 2-(trimethylsilyl)ethyl 4-(iodomethyl)benzoate (II). The 6-O-silylated gamma-cyclodextrin (III) is then condensed with (iodomethyl)benzoate (II) in the presence of BaO/Ba(OH)2 to produce the per-2-O-alkylated cyclodextrin (IV).

Simultaneous deprotection of the 6-O-t-butyldimethylsilyl and the (trimethylsilyl)ethyl ester groups of (IV) is accomplished by treatment with tetrabutylammonium fluoride in refluxing THF. The resultant cyclodextrin octa-carboxylic acid is finally isolated after conversion to the corresponding octa-sodium salt.