Spatane diterpenes

Gerwick, W.H. Fenical, W. (1983) Spatane diterpenes from the tropical algae Spatoglossum schmittii and Spatoglossum haleii. J. Org. Chem., 48, 3325-9. 

This stereocontrol is useful in a synthesis of a spatane diterpene (5). Thus hydride reduction of 3 affords only 4. In this case the syw-influence of the hydroxyl group is... 

A single electron transfer is again involved in formation of the ketone (14) together with the well-known intramolecular adduct (15) when carvone is irradiated in the presence of triethylamine (Givens et al.). In related work, Bischof and Mattay showed that the presence of triethylamine deflected the normal course of intramolecular photoaddition within the enones (16) to produce the spiro compounds (17) preferentially. Regio- and stereospecific adducts from cyclopentenones and the bicyclo[2.2.1]heptene (18) have been used by Salomon et al. as a route to spatane diterpenes. Photoadditions of alkenes to enones can give oxetans and/or cyclobutanes. Cruciani et al. have reported that the use of acetonitrile as solvent favours the formation of cyclobutanes. The oxetanes may be formed via a contact ion pair whereas the cyclobutanes may arise from an exciplex. 

Spatane diterpenes are a class of naturally occurring compounds that contain a fused cyclobutane ring in the core skeleton. Spatol 87 (Figure 19.8) is a representative member of this class of compounds that has garnered considerable interest due to its antitumor activity [51]. Harmata et al. used a [4+3] cycloaddition of a halogenated cyclic ketone followed by a quasi-Favorskii rearrangement to formally... 

Salomon, R.G., Sachinvala, N.D., Raychaudhuri, S.R., and Miller, D.B. (1984) Stereocontrol of Michael hydride reducfion by a remote hydroxyl group a strategy for stereorational total synthesis of spatane diterpenes. J. Am. Chem. Soc., 106,2211-2213. 

Dolabellanes and spatanes have been isolated from Panamanian brown seaweeds, but these diterpene skeletons are also known from related species from other areas, the first ones from the Mediterranean and the second ones from AustraEa, Sri Lanka, and India. 

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