title: Total synthesis of nominal gobienine A.
abstract: The lichen-derived glycoconjugate gobienine A is structurally more complex than most glycolipids isolated from higher plants by virtue of the all-cis substituted γ-lactone substructure embedded into its macrocyclic frame. A concise entry into this very epimerization-prone and hence challenging structural motif is presented, which relies on an enantioselective cyanohydrin formation, an intramolecular Blaise reaction, a palladium-catalyzed alkoxycarbonylation, and a diastereoselective hydrogenation of the tetrasubstituted alkene in the resulting butenolide. This strategy, in combination with ring-closing olefin metathesis for the formation of the macrocyclic perimeter, allowed the proposed structure of gobienine A (1) to be formed in high overall yield. The recorded spectral data show that the structure originally attributed to gobienine A is incorrect and that it is not the epimerization-prone ester site on the butanolide ring that is the locus of misassignment; rather, the discrepancy must be more profound.
authors.affiliation: Max-Planck-Institut für Kohlenforschung, 45470 Mülheim/Ruhr, Germany.
authors.forename: Azusa
authors.initials: A
authors.lastname: Kondoh
authors.forename: Alexander
authors.initials: A
authors.lastname: Arlt
authors.forename: Barbara
authors.initials: B
authors.lastname: Gabor
authors.forename: Alois
authors.initials: A
authors.lastname: Fürstner
mesh_terms: D000475:Alkenes / Q000737:chemistry; D006017:Glycolipids / Q000138:chemical synthesis* / Q000737:chemistry*; D006865:Hydrogenation; D007783:Lactones / Q000138:chemical synthesis / Q000737:chemistry; D008011:Lichens / Q000737:chemistry; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry
chemical_list: D000475:Alkenes; D006017:Glycolipids; D007783:Lactones; C447020:gobienine A; D010165:Palladium