title: Structure revision and synthesis of a novel labdane diterpenoid from Zingiber ottensii.
abstract: The structure of ottensinin, a recently reported constituent of the medicinal plant Zingiber ottensii, was revised by re-evaluation of available NMR data from alpha-ylidenebutenolide 1 to gamma-pyrone 2, whose rearranged labdane skeleton is unprecedented. Structure 2 was proven by synthesis from (+)-sclareolide (nine steps, 27% overall yield) and was further validated by X-ray diffraction analysis of our synthetic sample. A plausible biosynthesis of 2 is proposed.
authors.affiliation: Département de Chimie, Université Laval, Quebec City, Quebec G1K 7P4, Canada. john.boukouvalas@chm.ulaval.ca
authors.forename: John
authors.initials: J
authors.lastname: Boukouvalas
authors.forename: Jian-Xin
authors.initials: JX
authors.lastname: Wang
mesh_terms: D018360:Crystallography, X-Ray; D004224:Diterpenes / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D011753:Pyrones / Q000138:chemical synthesis* / Q000737:chemistry*; D030521:Zingiberaceae / Q000737:chemistry*
chemical_list: D004224:Diterpenes; D011753:Pyrones; C532302:ottensinin; C109395:sclareolide