title: Stereoselective synthesis of (+)-loline alkaloid skeleton.
abstract: The loline alkaloids present a compact polycyclic pyrrolizidine skeleton and contain a strained five-membered ethereal bridge, structural features that have proven challenging for synthetic chemists to incorporate since the discovery of this natural product family more than 100 years ago. These alkaloids are produced by mutualistic fungal symbionts (endophytes) living on certain species of pasture grasses and protect the host plant from insect herbivory. The asymmetric total synthesis of loline alkaloids is reported and extends our first-generation (racemic) synthesis of this alkaloid family. Key to the synthesis is a diastereoselective tethered aminohydroxylation of a homoallylic carbamate function and a Petasis Borono-Mannich addition.
authors.affiliation: Department of Chemistry, The College of William & Mary , P.O. Box 8795, Williamsburg, Virginia 23187, United States.
authors.forename: Kelsey E
authors.initials: KE
authors.lastname: Miller
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Wright
authors.forename: Margaret K
authors.initials: MK
authors.lastname: Olesen
authors.forename: M Todd
authors.initials: MT
authors.lastname: Hovey
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Scheerer
mesh_terms: D000470:Alkaloids / Q000138:chemical synthesis / Q000737:chemistry*; D001669:Biochemical Phenomena; D002219:Carbamates / Q000737:chemistry*; D005658:Fungi / Q000737:chemistry*; D015394:Molecular Structure; D011083:Polycyclic Compounds / Q000737:chemistry*
chemical_list: D000470:Alkaloids; D002219:Carbamates; D011083:Polycyclic Compounds; C059478:loline