title: Total synthesis of sordaricin.
abstract: An enantioconvergent total synthesis of sordaricin (3), the diterpene aglycon of an important class of antifungal compounds, is described. Two approaches were explored, the first of which utilized a possible biogenetic intramolecular [4 + 2] cycloaddition to form the complete carbon skeleton of the target molecule as a single regioisomer 30. A second approach employed a tandem cycloreversion/intramolecular [4 + 2] cycloaddition process to afford not only the desired product 30 but also significant quantities of the undesired regioisomer iso-30. An investigation into the reasons for the difference in regioselectivity between these two reactions revealed the intervention of a cycloreversion/cycloaddition pathway at elevated temperatures leading to the formation of iso-30. Experimental evidence supports the hypothesis that iso-30 is the more thermodynamically stable of the two regioisomers.
authors.affiliation: Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia. mander@rsc.anu.edu.au
authors.forename: Lewis N
authors.initials: LN
authors.lastname: Mander
authors.forename: Regan J
authors.initials: RJ
authors.lastname: Thomson
mesh_terms: D000935:Antifungal Agents / Q000138:chemical synthesis*; D004224:Diterpenes; D008968:Molecular Conformation
chemical_list: D000935:Antifungal Agents; D004224:Diterpenes; C116705:sordaricin