title: Total synthesis of aignopsanes, a class of sesquiterpenes: (+)-aignopsanoic acid A, (-)-methyl aignopsanoate A, and (-)-isoaignopsanoic A.
abstract: A general strategy for the synthesis of aignopsanes, a new family of sesquiterpene natural products of marine origin, is presented. The total synthesis of (+)-aignopsanoic acid A (1), (-)-methyl aignopsanoate A (2), and (-)-isoaignopsanoic A (3) has been achieved and their absolute configuration confirmed. (+)-Microcionin-1 (4), a structurally related furanosesquiterpene isolated in both enantiomeric forms from marine sponges, was also synthesized and its absolute configuration established in an unambiguous way. Interestingly, we report that (+)-microcionin-1 (4), can be converted by a simple oxidation process to aignopsanoic acid A (1). This transformation supports the hypothesis that (+)-microcionin-1 (4) may be an intermediate in the biosynthesis of aignopsanes.
authors.affiliation: University of Bern, Department of Chemistry and Biochemistry, Freiestrasse 3, 3012 Bern (Switzerland).
authors.forename: Cédric
authors.initials: C
authors.lastname: Bürki
authors.forename: Josep
authors.initials: J
authors.lastname: Bonjoch
authors.forename: Ben
authors.initials: B
authors.lastname: Bradshaw
authors.forename: Giorgio
authors.initials: G
authors.lastname: Villa
authors.forename: Philippe
authors.initials: P
authors.lastname: Renaud
mesh_terms: D000475:Alkenes / Q000737:chemistry; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D007659:Ketones / Q000737:chemistry; D008968:Molecular Conformation; D010084:Oxidation-Reduction; D012717:Sesquiterpenes / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000475:Alkenes; D007659:Ketones; D012717:Sesquiterpenes; C540379:aignopsanoic acid A; C000600694:isoaignopsanoic A; C540380:methyl aignopsanoate A
keywords: Wieland-Miescher ketone; biosynthesis; furanosesquiterpenes; natural products; total synthesis