Formal Synthesis of Amipurimycin and 4'-Deoxymiharamycin B by Way of Sequential Asymmetric Metal Catalysis.

Herein, we describe a highly efficient formal synthesis of nucleoside antibiotics amipurimycin and 4'-deoxymiharamycin B. A signature event is highlighted by the sequential metal catalysis combining (i) Pd-catalyzed asymmetric hydroalkoxylation of an alkoxyallene; (ii) Ru-catalyzed enyne-methathesis, and (iii) Os-catalyzed dihydroxylation. Remarkably, this atom-efficient sequence allows for the construction of a 3'-branched pyranose core structure in only four steps from readily available Garner's aldehyde.