[reaction: see text] The enantioselective synthesis of a 7,11-dihydroxyguaianolide bearing the stereochemistry present in thapsigargin, a potent and selective inhibitor of the Ca(2+) SERCA-ATPase pumps, is described. Starting from (+)-dihydrocarvone, the synthesis presents two key steps. The first one involves the photochemical rearrangement of a gamma,delta-unsaturated ketone eudesmane into the corresponding guaiane. The second step consists of the regioselective oxidation of an unprotected tetrahydroxylated ketone to provide a dihydroxylactone with the required stereochemistry.

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Halogenation Halogenation O 0235 CeCl 3 /NaClO: A Safe and Efficient Reagent for the Allylic Chlorination of Terminal Olefins. -An operationally simple method is described for the high-yielding title reaction. -(MORENO-DORADO, F. J.; GUERRA, F. M.; MANZANO, F. L.; ALADRO, F. J.; JORGE, Z. D.; MASSANET*, G. M.; Tetrahedron Lett. 44 (2003) 35, 6691-6693; Dep. Quim. Org., Fac. Cienc., Univ. Cadiz, E-11510 Puerto Real, Cadiz, Spain; Eng.) -Mais 48-048