ORGN 26 |
| Pyranones and furanones are common structural units found in a large number of natural products. The development of synthetic methods leading to these compounds in enantiopure form is therefore still in demand. Previously we demonstrated that Pd-mediated oxidative and non-oxidative cyclisations of enantioenriched β-hydroxyenones can be successfully applied to the synthesis of enantioenriched dihydro- and tetrahydropyranones. Here we report detailed studies of the potential of β-hydroxyynones as precursors of enantioenriched furanones and pyranones. We have established three different strategies to ring closure of β-hydroxyynones: tandem Wacker-Heck oxidative Pd-mediated cyclisation, Lewis acid catalyzed intramolecular Michael conjugated addition, as well as organocatalytic ring closures. All reactions proceed with moderate to high yields and more often without racemisation.
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Asymmetric Reactions and Syntheses
8:00 AM-12:20 PM, Sunday, 10 September 2006 Moscone Center -- Room 131, Oral
Division of Organic Chemistry |
