An approach to the synthesis and attachment of scillabiose to steroids

Hellebrin and transvaalin are two naturally occurring saponins with biological activity. In the present paper, we describe a high yielding route to the synthesis and coupling of their shared glycone, scillabiose, to a model steroid. A convergent coupling strategy utilizing a scillabiose-based glycosyl donor was devised for the glycosylation. This convergent approach is appealing due to its high efficiency and simple deprotection procedure and may find further use in total synthesis of naturally occurring saponins and related compounds sharing the same glycone. Due to the widespread occurrence of this glycone in nature, the complete NMR spectroscopic characterization of all compounds prepared herein is provided as reference material. In addition, glycosylations were performed with the monosaccharide constituents of scillabiose, thereby providing a limited series of glycosylated steroids for potential future evaluation of the effects of the glycone on the overall biological activity.

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► Hellebrin and transvaalin are two naturally occurring saponins widely known for their biological activities.
► These two saponins share the same glycone, scillabiose.
► Here, we present a high yielding method for the synthesis and attachment of this glycone to a model substrate based on a block approach.
► The full NMR spectroscopic characterization of the glycosylated steroids were carried out utilizing a combination of several NMR experiments and spectral simulations and is presented in the paper in detail.