202339-63-7Relevant academic research and scientific papers
Total synthesis of (±)- and (+)-valienamine via a strategy derived from new palladium-catalyzed reactions
Trost, Barry M.,Chupak, Louis S.,Luebbers, Thomas
, p. 1732 - 1740 (2007/10/03)
A new strategy toward glycosidase inhibitors, represented by valienamine, which is such an inhibitor itself as well as a critical unit of pseudooligosaccharides that function this way, evolved from two newly developed palladium-catalyzed reactions. The applicability of a palladium(0)-catalyzed net regioselective cis-hydroxyamination derives from the reaction of vinyl epoxides with isocyanates. The utilization of a cocatalyst in this reaction is required in this case and may prove generally useful. A bidentate phosphate proved to be the most effective ligand. The requisite substrate was available via a Diels-Alder protocol and allowed the obtention of (±)-valienamine in only seven steps. The inability to perform the Diels-Alder reaction asymmetrically led to a different asymmetric synthesis of the pivotal epoxide intermediate in enantiomerically pure form, which derived from asymmetric palladium-catalyzed reactions. Using the desymmetrization of meso enedicarboxylates, the net equivalence of an asymmetric cis-hydroxycarboxylation led to the enantiomerically pure desired epoxide. (+)-Valienamine was available in 14 steps by this route.
