Complete Sets of Monosubstituted γ-Cyclodextrins as Precursors for Further Synthesis

Regioselective alkylation of gamma-cyclodextrin with allyl or propargyl bromide, using optimized reaction conditions, followed by peracetylation of the remaining hydroxyl groups and separation of isomers resulted in the set of peracetylated 2(I)-O-, 3(I)-O- and 6(I)-O-alkylated cyclodextrins in up to 19% yields. Ozonolysis or oxidative cleavage of peracetylated allyl derivatives resulted in a complete set of peracetylated 2(I)-O, 3(I)-O-, and 6(I)-O-formylmethyl or -carboxymethyl derivatives. All of these derivatives are useful precursors for further preparation of regioselectively monosubstituted derivatives of gamma-cyclodextrin.