A very efficient method for synthesizing spirolactones is reported. Treatment of δ,ε-unsaturated carboxylic acids with iodine and triphenylphosphine under mild conditions leads to the corresponding spiro γ-lactones in high yield and with complete stereoselectivity. Utilizing this, the first synthesis of the terpene spirolactones (-)-isoambreinolide, (+)-vitexifolin D and (+)-vitedoin B has been achieved.
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http://dx.doi.org/10.1039/c3ob42122h | DOI Listing |
Org Biomol Chem
January 2014
Departamento de Química Orgánica, Facultad de Ciencias, Instituto de Biotecnología, Universidad de Granada, 18071 Granada, Spain.
A very efficient method for synthesizing spirolactones is reported. Treatment of δ,ε-unsaturated carboxylic acids with iodine and triphenylphosphine under mild conditions leads to the corresponding spiro γ-lactones in high yield and with complete stereoselectivity. Utilizing this, the first synthesis of the terpene spirolactones (-)-isoambreinolide, (+)-vitexifolin D and (+)-vitedoin B has been achieved.
View Article and Find Full Text PDFJ Nat Prod
April 2002
School of Agriculture, Kyushu Tokai University, Choyo 5435, Aso, Kumamoto 869-1404, Japan.
A new labdane-type diterpene, vitexifolin A (1), a new clerodane-type diterpene, vitexifolin B (2), a new abeoabietane-type diterpene, vitexifolin C (3), and two new norlabdane-type diterpenes, vitexifolin D (4) and vitexifolin E (5), were isolated from the fruits of Vitex rotundifolia, along with a known halimane-type diterpene, vitetrifolin D (6), two known norlabdane-type diterpenes, trisnor-gamma-lactone (7) and iso-ambreinolide (8), and three known flavonoids, casticin (9), artemetin (10), and 5,3'-dihydroxy-6,7,4'-trimethoxyflavanone (11). Their chemical structures were determined on the basis of spectroscopic data. Casticin (9) exhibited considerable growth inhibitory activity against human lung cancer cells (PC-12) and human colon cancer cells (HCT116) using the MTT assay.
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