Synthetic Study toward Saccharomicin Based upon Asymmetric Metal Catalysis.

Here, we report a de novo metal-catalyzed approach toward the stereoselective glycosidic bond formation in saccharomicin. The signature step is highlighted by the Pd-catalyzed asymmetric coupling of ene-alkoxyallenes and highly functionalized alcohol substrates. The reaction showed high chemo-, regio-, and ligand-driven diastereoselectivity. In combination with the ring-closing metathesis and late-stage functionalization, this method led to highly efficient synthesis of saccharosamine-rhamnose and rhamnose-fucose fragments.