title: Nitrenium ion-mediated alkene bis-cyclofunctionalization: total synthesis of (-)-swainsonine.
abstract: The total synthesis of (-)-swainsonine from 2,3-O-isopropylidene-D-erythrose in 12 steps and an overall yield of 28% is reported. The pivotal transformation in our route to this indolizidine alkaloid is the formation of the pyrrolidine ring and C-8a/8 stereodiad through the diastereoselective, bis-cyclofunctionalization of an γ,δ-unsaturated O-alkyl hydroxamate. This transformation is believed to proceed via the intramolecular capture of an N-acyl-N-alkoxyaziridinium ion generated by the diastereoselective addition of a singlet acylnitrenium ion to the pendant alkene.
authors.affiliation: Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, Illinois 60607-7061, United States. wardropd@uic.edu
authors.forename: Duncan J
authors.initials: DJ
authors.lastname: Wardrop
authors.forename: Edward G
authors.initials: EG
authors.lastname: Bowen
mesh_terms: D000475:Alkenes / Q000737:chemistry*; D002412:Cations / Q000737:chemistry; D003500:Cyclization; D015394:Molecular Structure; D017672:Nitrogen Compounds / Q000737:chemistry*; D010084:Oxidation-Reduction; D017026:Swainsonine / Q000138:chemical synthesis*
chemical_list: D000475:Alkenes; D002412:Cations; D017672:Nitrogen Compounds; D017026:Swainsonine