Synthesis and supramolecular properties of regioisomers of mononaphthylallyl derivatives of gamma-cyclodextrin
Abstrakt
Monosubstituted derivatives of gamma-cyclodextrin (gamma-CD) are suitable building blocks for supramolecular polymers, and can also serve as precursors for the synthesis of other regioselectively monosubstituted gamma-CD derivatives. We prepared a set of monosubstituted 2(I)-O-, 3(I)-O-, and 6(I)-O-(3-(naphthalen-2-yl)prop-2-en-1-yl) derivatives of gamma-CD using two different methods.
A key step of the first synthetic procedure is a cross-metathesis between previously described regioisomers of mono-O-allyl derivatives of gamma-CD and 2-vinylnaphthalene which gives yields of about 16-25% (2-5% starting from gamma-CD). To increase the overall yields, we have developed another method, based on a direct alkylation of gamma-CD with 3-(naphthalen-2-yl)allyl chloride as the alkylating reagent.
Highly regioselective reaction conditions, which differ for each regioisomer in a used base, gave the monosubstituted isomers in yields between 12-19%). Supramolecular properties of these derivatives were studied by DLS, ITC, NMR, and Cryo-TEM.