Unified synthesis of eudesmanolides, combining biomimetic strategies with homogeneous catalysis and free-radical chemistry.
[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.
Barrero
Alejandro F
AF
Department of Organic Chemistry, Faculty of Sciences, Campus Fuentenueva s/n, University of Granada, E-18071 Granada, Spain.
Rosales
Antonio
A
Cuerva
Juan M
JM
Oltra
J Enrique
JE
D032701:Biomimetics; D002384:Catalysis; D004579:Electron Transport; D005609:Free Radicals / Q000737:chemistry; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D012717:Sesquiterpenes / Q000737:chemistry*
D005609:Free Radicals; D007202:Indicators and Reagents; D012717:Sesquiterpenes; C476916:eudesmanolide