Oidiolactones

Although the epoxidation of the A7 double bond of type C podolactones has been reported as being unsuccessful after several conditions, when C-14 position is not substituted, the epoxidation of this double bond of dilactone 68 is achieved to synthesize oidiolactone C (61) [80]. 

Synthesis of Oidiolactone C Starting from Communic Acids... 

The second synthetic approach to oidiolactone C (61) is summarized in Scheme 20. This route also commences with the ozonolysis of trans-communic acid 180. Now, when this compound was exposed to ozone in excess, keto aldehyde 187 was obtained in 76% yield. The key step in this approach was the y-lactone closure via chemoselective reduction of the lactone moiety on compound 189 through a SN2 mechanism. Compound 189 could be prepared by saponification of the corresponding methyl ester with sodium propanethiolate. Once the primary alcohol is oxidized, the completion of the synthesis of key lactone 103 only requires the allylic oxidation of the C-17 methyl with concomitant closure of the 8-lactone. This conversion was achieved with Se02 in refluxing acetic acid to give 103 in 51% yield. 

Biologically active secondary metabolites from fungi. 12. Oidiolactones A-F, labdane diterpene derivatives isolated from Oidiodendron truncata. John, M. Krohn, K. Florke, U. Aust, H-J. Draeger, S. Schulz, B. J. Nat. Prod. 1999, 62, 1218-1221. 

The First Synthesis of the Antifungal Oidiolactone C from rrans-Communic Acid Cytotoxic and Antimicrobial Activity in Podolactone-related Compounds. Barrero, A.F. Arseniyadis, S. Quflez del Moral, J. F. Herrador, M. M. Valdivia, M. Jimenez, D. J. Org. Chem. 2002,67,2501-2508. 

Preparation of bioactive podolactones via a new Pd-catalysed bislactonization reaction. Synthesis of oidiolactone C. Barrero, A. F. Quflez del Moral, J. F. Cuerva, J. M. Cabrera, E. Jimenez-Gonzalez, D. Tetrahedron Lett. 2000, 41, 5203-5206. 

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