A Practical Route to Neokotalanol and Its Natural Analogues, Sulfonium Sugars With Antidiabetic Activities

An efficient and divergent approach toward the synthesis of all the four de‐O‐sulfonated sulfonium type α‐glucosidase inhibitors originally isolated from plants of genus Salacia was reported for the first time. The key strategy features a coupling reaction between thiol derivatives and a diiodide counterpart. The newly designed thiol coupling partner presented high chemical stability, while the other coupling partner diiodide could be easily obtained with increased overall yields when compared with conventional routes. The intermolecular nucleophilic substitution reaction followed by a diastereoselective intramolecular cyclization provided the target five‐member sulfonium salt structure which was connected in an α‐orientation to poly hydroxylated side chain moiety.

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