title: Tandem reduction-chloroallylboration of esters: asymmetric synthesis of lamoxirene, the spermatozoid releasing and attracting pheromone of the laminariales (Phaeophyceae).
abstract: The asymmetric synthesis of all four stereoisomers of lamoxirene (cis-2-cyclohepta-2,5-dienyl-3-vinyloxirane), the spermatozoid-releasing and -attracting pheromone of the Laminariales (Phaeophyceae), is reported. Chiral ethyl cyclohepta-2,5-diene carboxylates, prepared by a divinylcyclopropane Cope rearrangement, were effectively alkylated by means of a novel tandem DIBAL-H reduction/asymmetric alpha-chloroallylboration using (Z)-gamma-chloroallyldiisopinocampheylboranes. The ensuing syn-alpha-chlorohydrins were transformed into the corresponding vinyloxiranes with DBU, providing all four isomers of the pheromone in good chemical and excellent optical yield (90-97% ee). Spermatozoid-release assays were conducted with the sympatrically growing species L. digitata, L. hyperborea, and L. saccharina and established (1'S,2R,3S)-1c as the most active isomer in all cases.
authors.affiliation: Max-Planck-Institute for Chemical Ecology, Jena, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Hertweck
authors.forename: W
authors.initials: W
authors.lastname: Boland
mesh_terms: D000478:Alkylation; D000498:Allyl Compounds / Q000138:chemical synthesis; D002264:Carboxylic Acids / Q000138:chemical synthesis; D003500:Cyclization; D005854:Germ Cells / Q000187:drug effects*; D007795:Laminaria / Q000378:metabolism*; D010675:Pheromones / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D012623:Seawater; D015398:Signal Transduction; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
chemical_list: D000498:Allyl Compounds; D002264:Carboxylic Acids; D010675:Pheromones