Total Synthesis of the Purported Structure of Branched Resin Glycosides Merremoside G and H₂

Abstract

The first total synthesis of the purported structure of branched resin glycosides merremoside G and H 2 is accomplished. A signature step is represented by the sequential transition-metal-catalyzed coupling of stable trisaccharide homoallylic alcohol and monosaccharide alkoxyallene to afford the pentasaccharide skeleton. This de novo strategy is conducted under mild conditions with no need of preactivation. In addition, it allows for efficient preparation of the target compounds in combination with late-stage functionalization.

Formal Synthesis of (+)-Sinefungin by Way of Sequential Asymmetric Metal Catalysis

“…We recently developed Pd-catalyzed asymmetric hydroalkoxylation of alkoxyallene, which evolved into a de novo glycosylation method upon combination with the ring-closing-metathesis (RCM) reaction . On the basis of this precedent, we envisioned that a related strategy would allow highly efficient access to sinefungin from commercially available cis -1,3-pentenediol.…”