Annonaceous acetogenins rings

As stated earlier, virtually all Annonaceous acetogenins possess a y-lactone at the terminus of the carbon chain. The known structural variations within this lactone ring ("A") are summarized in Figure 5. Although the absolute configuration at C(36) in... 

The total synthesis of (+)-asimicin, which belongs to the family of Annonaceous acetogenins, was completed by E. Keinan and co-workers. In order to create one of the tetrahydrofuran rings stereospecifically, an intramolecular Williamson ether synthesis was performed between a secondary alcohol and a secondary mesylate using pyridine as the base. 

Fig. (2). Types of the terminal y-lactone rings systems in Annonaceous acetogenins.

Annonaceous Acetogenins with Mono-Tetrahydrofuran (THF) Ring... 

Annonaceous acetogenins, potent bioactive secondary metabolites from several species of Annonaceae, usually contain 35 or 37 carbon atoms, one or two tetrahydrofiiran rings, and a 7-lactone with five to eight carbinol asymmetric centers. Corossolone (890), a naturally... 

Systematic synthesis of diastereomeric poly-THF ring cores and total synthesis of antitumor Annonaceous acetogenins 06SL993. 

In addition to the (+)-c/s-solamin example outlined above, the Donohoe group has also applied their method in the synthesis of the annonaceous acetogenin (+)-sylvaticin (Scheme 51) [56], (for the application of the oxidative cyclization chemistry to bicyclic ring systems see [57]). Exposure of a mixture of tetradeca-tetraene isomers (commercially available as a mixture of three stereoisomers) or the pure , -isomer to AD-mix-a gave 191 in an 18 % yield after bis-acetonide... 

Temporary Silicon-Tethered Ring-Closing Metathesis Reactions 237 8.2.2.3 Annonaceous Acetogenins... 

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