title: On the origin of siphonariid polypropionates: total synthesis of caloundrin B and its isomerization to siphonarin B.
abstract: Enantioselective synthesis of the enantiomer of caloundrin B was achieved by strategic aldol coupling of an enantiopure trioxaadamantane-containing ketone with a racemic pyrone-containing aldehyde via kinetic resolution. In the presence of imidazole, ent-caloundrin B is cleanly isomerized to ent-siphonarin B confirming the proposed structure and absolute configuration for caloundrin B and establishing that it is a plausible biosynthetic product from which siphonarin B and baconipyrones A and C can originate.
authors.affiliation: Department of Chemistry, University of Saskatchewan, 110 Science Place, Saskatoon SK S7N 5C9, Canada.
authors.forename: Fabiola
authors.initials: F
authors.lastname: Becerril-Jiménez
authors.forename: Dale E
authors.initials: DE
authors.lastname: Ward
mesh_terms: D000218:Adamantane / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry; D000447:Aldehydes / Q000737:chemistry; D000818:Animals; D001688:Biological Products; D007659:Ketones / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D008974:Mollusca / Q000737:chemistry; D011753:Pyrones / Q000138:chemical synthesis / Q000737:chemistry; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000447:Aldehydes; D001688:Biological Products; D007659:Ketones; D011753:Pyrones; D013141:Spiro Compounds; C539669:caloundrin B; C448330:siphonarin B; C116609:3-hydroxybutanal; D000218:Adamantane