Cladiellin diterpene

The most general method for the synthesis of tetrahydrofurans based upon the IMSC methodology was developed by Overman et al. [53, 54, 94—96] For example, condensation of alcohol 221 with an aldehyde or a ketone in the presence of a Lewis acid leads to the formation of the carbocations 222a,b. The tertiary carboca-tion 222a undergoes a pinacol rearrangement and forms the desired heterocycle 224 (Scheme 13.82). Overman et al. used this approach during the synthesis of the various cladiellin diterpenes, which possess the core skeleton 224 [53]. 

Eunicellanes and (infrequently) asbestinanes are diterpenes of marine origin, including eunicelline from the alga Eunicella stricta and cladielline found in some Cladiella species. Asbestinanes such as (-)-asbestinine 2 are characteristic of the gorgonia Briareum asbestinum (Araceae). 

Hochlowski, J.E., and D.J. Faulkner A Diterpene Related to Cladiellin from a Pacific Soft Coral. Tetrahedron Lett. 21, 4055 (1980). 

Corminboeuf, O., Overman, L.E., and Pennington, L.D. (2009) A unified strategy for enantioselective total synthesis of cladiellin and briarellin diterpenes Total synthesis of briarellins E and F and the putative stmcture of alcyonin and revision of its stmcture assignment. J. Org. Chem., 74, 5458-5470. 

Hochlowski, J.E. and Faulkner, D.J. (1980) A diterpene related to cladiellin from a Pacific soft coral. Tetrahedron Lett., 21, 4055-4056. 

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