Unified synthesis of caged Garcinia natural products based on a site-selective Claisen/Diels-Alder/Claisen rearrangement.
A unified synthetic strategy toward caged Garcinia natural products has been designed and implemented. Central to the strategy is a tandem Claisen/Diels-Alder/Claisen rearrangement of a suitably substituted xanthone precursor to form forbesione (1a). Serving as a template, forbesione is then used to deliver representative members of this family, including desoxygaudichaudione A (4), desoxymorellin (5), and gambogin (10). Studies on the timing of this reaction cascade suggest that the C-ring Claisen/Diels-Alder rearrangement proceeds initially and is followed by the A-ring Claisen reaction. The electronic and steric effects that govern the outcome of this cascade are presented.
Tisdale
Eric J
EJ
Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, MC 0358, La Jolla, CA 92093-0358, USA.
Slobodov
Irina
I
Theodorakis
Emmanuel A
EA
D001688:Biological Products / Q000138:chemical synthesis* / Q000737:chemistry*; D001952:Bridged-Ring Compounds / Q000138:chemical synthesis / Q000737:chemistry; D002625:Chemistry, Organic / Q000379:methods; D029760:Garcinia / Q000737:chemistry*; D006571:Heterocyclic Compounds / Q000138:chemical synthesis / Q000737:chemistry; D007202:Indicators and Reagents; D015394:Molecular Structure; D014966:Xanthenes / Q000138:chemical synthesis / Q000737:chemistry; D044004:Xanthones / Q000138:chemical synthesis / Q000737:chemistry
D001688:Biological Products; D001952:Bridged-Ring Compounds; D006571:Heterocyclic Compounds; D007202:Indicators and Reagents; D014966:Xanthenes; D044004:Xanthones; C482270:desoxymorellin; C482271:forbesione; C458581:gaudichaudione A; C052659:gambogic acid