title: Enantioselective synthesis of (+)-obolactone based on a symmetry-breaking Wacker monooxidation of a diene.
abstract: A concise synthesis of the dihydro-α-pyrone/dihydro-γ-pyrone natural product (+)-obolactone (13) is disclosed. The dienediol acetonide 23 (≥97% ee) was obtained from 1,5-dichloropentane-2,4-dione in four steps. A Wacker monooxidation of 23 furnished the monoketone 24 in 64% yield. The OH group of the ensuing dihydro-γ-pyrone 31 was esterified under Mitsunobu conditions with cinnamic acid (→ 80% inversion and 20% retention of configuration). A ring-closing metathesis formed the dihydro-α-pyrone moiety of the target in the terminating step.
authors: Institut für Organische Chemie, Albert-Ludwigs-Universität, Albertstraße 21, 79104 Freiburg im Breisgau, Germany.
authors: Patrick
authors: P
authors: Walleser
authors: Reinhard
authors: R
authors: Brückner
mesh_terms: D001688:Biological Products / Q000138:chemical synthesis* / Q000737:chemistry; D007783:Lactones / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D010084:Oxidation-Reduction; D011090:Polyenes / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D001688:Biological Products; D007783:Lactones; D011090:Polyenes; C516119:obolactone