Easy Access to Modified Cyclodextrins by an Intramolecular Radical Approach

Radical Dehydroxymethylative Fluorination of Carbohydrates and Divergent Transformations of the Resulting Reverse Glycosyl Fluorides

A mild and convenient method for the synthesis of reverse glycosyl fluorides (RGFs) has been developed that is based on the silver-promoted radical dehydroxymethylative fluorination of carbohydrates. A salient feature of the reaction is that furanoid and pyranoid carbohydrates furnish structurally diverse RGFs bearing a wide variety of functional groups in good to excellent yields. Intramolecular hydrogen atom transfer experiments revealed that the reaction involves an underexploited radical fluorination that proceeds via β-fragmentation of sugar-derived primary alkoxyl radicals. Structurally divergent RGFs were obtained by catalytic C-F bond activation, and our method thus offers a concise and efficient strategy for the synthesis of reverse glycosides by late-stage diversification of RGFs. The potential of this method is showcased by the preparation and diversification of sotagliflozin, leading to the discovery of a promising SGLT2 inhibitor candidate.

Construction of Crowning β-cyclodextrin with Temperature Response and Efficient Properties of Host-Guest Inclusion

Promoting a drug inclusion proportion in hydrophobic cavity of β-cyclodextrin using simple methods is a highly ambitious task. Herein, we report the crowning β-cyclodextrins formed by intramolecular hydrogen bonding interaction, which has greatly prolonged the cavity depth of β-cyclodextrin, and therefore further efficiently improved the inclusion proportion to complex drug molecule (vitamin E). Furthermore, the self-assembly behaviors, controllable release, and antioxidant properties of vitamin E embedded into the cavity of crowning β-cyclodextrins was investigated, and host-guest inclusions exhibited temperature-responsive controlled release, excellent antioxidant activity, and photostability.