Structure and stereochemistry of triflavanoids containing both ether and carbon-carbon interflavanyl bonds.
The first triflavanoids with both C-C and C-O-C interflavanyl bonds, epioritin-(4beta-->6)-epioritin-(4alpha-->4)-epioritin-4beta-ol, epioritin-(4beta-->3)-epioritin-(4beta-->6)-epioritin-4beta-ol and epioritin-(4beta-->3)-epioritin-(4beta-->6)-epimesquitol-4alpha-ol, were identified in the heartwood of Acacia caffra. The ethereal interflavanyl bond is readily susceptible to reductive cleavage with sodium cyanoborohydride in trifluoroacetic acid/dichloromethane which hence permits the unequivocal assignment of the absolute configuration of constituent flavanyl units.
Bennie
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L
Department of Chemistry, University of the Orange Free State, PO Box 339, 9300, Bloemfontein, South Africa.
Coetzee
J
J
Malan
E
E
Ferreira
D
D
D004987:Ethers; D005419:Flavonoids / Q000737:chemistry* / Q000302:isolation & purification; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008968:Molecular Conformation; D010636:Phenols / Q000737:chemistry* / Q000302:isolation & purification; D019685:Rosales / Q000737:chemistry*; D012997:Solvents; D014934:Wood
D004987:Ethers; D005419:Flavonoids; D007202:Indicators and Reagents; D010636:Phenols; D012997:Solvents