title: Unified synthesis of eudesmanolides, combining biomimetic strategies with homogeneous catalysis and free-radical chemistry.
abstract: [reaction: see text] A general procedure for the synthesis of both 12,6- and 12,8-eudesmanolides has been developed. The key step is the titanocene-catalyzed radical cyclization of accessible epoxygermacrolides. The novel reagent 2,4,6-trimethyl-1-trimethylsilylpyridinium chloride, both compatible with oxiranes and capable of regenerating Cp(2)TiCl(2) from Cp(2)Ti(Cl)H and Cp(2)Ti(Cl)OAc, played an important role in the catalytic cycle leading to exocyclic alkenes.
authors.affiliation: Department of Organic Chemistry, Faculty of Sciences, Campus Fuentenueva s/n, University of Granada, E-18071 Granada, Spain.
authors.forename: Alejandro F
authors.initials: AF
authors.lastname: Barrero
authors.forename: Antonio
authors.initials: A
authors.lastname: Rosales
authors.forename: Juan M
authors.initials: JM
authors.lastname: Cuerva
authors.forename: J Enrique
authors.initials: JE
authors.lastname: Oltra
mesh_terms: D032701:Biomimetics; D002384:Catalysis; D004579:Electron Transport; D005609:Free Radicals / Q000737:chemistry; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D012717:Sesquiterpenes / Q000737:chemistry*
chemical_list: D005609:Free Radicals; D007202:Indicators and Reagents; D012717:Sesquiterpenes; C476916:eudesmanolide