title: Synthesis of bridged oxafenestranes from pleuromutilin.
abstract: Fenestranes are an intriguing class of highly strained molecules possessing a quaternary carbon with bonds that deviate from the canonical tetrahedral geometry. Herein we report the discovery that the natural product pleuromutilin can be used as a structurally complex starting material for the synthesis of a series of bridged cis,cis,cis,cis-[4.5.5.5]- and cis,cis,cis,cis-[4.5.7.5]oxafenestranes through a carbocation rearrangement cascade. X-ray crystallographic analysis of several cis,cis,cis,cis-[4.5.5.5]oxafenestranes shows a significant planarization of the central tetracoordinate carbon atom and demonstrates the influence of bridgehead substituents and bridging rings on planarity.
authors.affiliation: Department of Chemistry, University of Illinois at Urbana-Champaign, 261 RAL, Box 36-5, 600 S. Mathews, Urbana, IL 61801 (USA).
authors.forename: Robert W
authors.initials: RW
authors.lastname: Hicklin
authors.forename: Tania L
authors.initials: TL
authors.lastname: López Silva
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Hergenrother
mesh_terms: D001688:Biological Products / Q000737:chemistry*; D004224:Diterpenes / Q000737:chemistry; D008958:Models, Molecular; D015394:Molecular Structure; D011083:Polycyclic Compounds; D013237:Stereoisomerism; D000097567:Pleuromutilins
chemical_list: D001688:Biological Products; D004224:Diterpenes; D011083:Polycyclic Compounds; D000097567:Pleuromutilins
keywords: fenestranes; natural products; planar tetracoordinate carbon atom; strained molecules