title: A new approach to (-)-swainsonine by ruthenium-catalyzed ring rearrangement.
abstract: A new enantioselective synthesis of the idolizidine alkaloid (-)-swainsonine 1 in 40% overall yield starting from the known oxazolidinone 6 is described. Throughout the synthesis, the high efficiency of metal-catalyzed reactions is illustrated. The key step is a new ruthenium-catalyzed metathesis rearrangement reaction. In this ring-closing/ring-opening tandem process, stereocenters are transferred from a ring to the olefinic side chain of the formed heterocycle. The metathesis precursor was obtained by palladium-catalyzed desymmetrization of cyclopentenediol. The synthesis was completed by functionalization of the terminal double bond, cyclization of the second ring, and diastereoselective dihydroxylation.
authors.affiliation: Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, Germany.
authors.forename: Nicole
authors.initials: N
authors.lastname: Buschmann
authors.forename: Anke
authors.initials: A
authors.lastname: Rückert
authors.forename: Siegfried
authors.initials: S
authors.lastname: Blechert
mesh_terms: D000470:Alkaloids / Q000737:chemistry*; D002384:Catalysis; D002625:Chemistry, Organic / Q000379:methods*; D002851:Chromatography, High Pressure Liquid; D003500:Cyclization; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D016961:Rhizobium leguminosarum / Q000737:chemistry; D012428:Ruthenium / Q000737:chemistry*; D013237:Stereoisomerism; D017026:Swainsonine / Q000032:analysis / Q000138:chemical synthesis*
chemical_list: D000470:Alkaloids; D012428:Ruthenium; D017026:Swainsonine