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Diisobutylaluminium hydride(DIBAL-H) promotes secondary rim regioselective bis-de-O-methylation of permethylatedβ-cyclodextrin (β-CD) to give diol 2.To gain an insight into the mechanism of this remarkable regioselective behavior,two corresponding permethylatedβ-CDs with an alcohol function at either 2- or 3-position were synthesized in our previous study.As a step further to this work,the two compounds were subjected to deoxygenation reaction with tributyltin hydride in the present of 2,2’- azobisisobutyronitrile affording the corresponding 2- and 3-deoxy permethylatedβ-CD derivatives(19 and 16).The structures of these two compounds were characterized by ID and 2D NMR and HRMS.Compounds 16 and 19 were unable to react with DIBALH which suggests that O-2~A and O-3~B are necessary for DIBAL-H promoted bis-de-O-methylation reaction of permethylatedβ-CD.
Diisobutylaluminium hydride (DIBAL-H) promotes secondary rim regioselective bis-de-O-methylation of permethylated β-cyclodextrin (β-CD) to give diol 2. Tuo gain an insight into the mechanism of this remarkable regioselective behavior, two corresponding permethylated β-CDs with an alcohol function at either 2- or 3-position were synthesized in our previous study. As a step further to this work, the two compounds were subjected to deoxygenation reaction with tributyltin hydride in the present of 2,2’- azobisisobutyronitrile affording the The structures of these two compounds were characterized by ID and 2D NMR and HRMS. Compounds 16 and 19 were unable to react with DIBALH which suggests that O-2 ~ 3-deoxyperthythylated β-CD derivatives (19 and 16) A and O-3 ~ B are necessary for DIBAL-H promoted bis-de-O-methylation reaction of permethylated β-CD.