title: Synthesis of stereoisomers of Artemisia and Chrysanthemum bis(acetylenic) enol ether spiroacetals.
abstract: An 11-step synthesis is described of two diastereomeric candidates for a bis(acetylenic) enol ether spiroacetal isolated from Chrysanthemum boreale. Key steps in the synthetic route include spiroacetal lactone alkylidenation and subseqent modified Cadiot-Chodkiewicz cross-coupling to install the bis(acetylenic) enol ether functionality. From NMR comparisons, neither of the candidates, whose structures were confirmed by single-crystal X-ray diffraction, correspond to the natural product, and a proposal for the correct structure is put forward.
authors.affiliation: Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK.
authors.forename: Boshen
authors.initials: B
authors.lastname: Wu
authors.forename: George C
authors.initials: GC
authors.lastname: Feast
authors.forename: Amber L
authors.initials: AL
authors.lastname: Thompson
authors.forename: Jeremy
authors.initials: J
authors.lastname: Robertson
mesh_terms: D000080:Acetals / Q000138:chemical synthesis* / Q000737:chemistry; D019306:Artemisia / Q000737:chemistry*; D031202:Chrysanthemum / Q000737:chemistry*; D007783:Lactones; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism; D014961:X-Ray Diffraction
chemical_list: D000080:Acetals; D007783:Lactones; D013141:Spiro Compounds