Cyclodecadienes monoepoxides

Transannular cyclizations of cyclodecadiene monoepoxides have been studied in exhaustive detail, particularly amongst natural germacranolides, because of their relevance to biogenetic models for the synthesis of eudesmane- and guaiane-type sesquiterpenes. " A full discussion of this topic is beyond the scope of this chapter, but the examples collected in equations (54-64) provide the reader with an in-... 

Stereoselective transannular cyclizations to hydroazulene systems are also described. These reactions are initiated by ionization of cyclodecenol to form an allylic cation or by oxirane ring opening in cyclodecadiene monoepoxides. 

T, E)-1,5-Cyclodecadiene monoepoxide reacts in the presence of sulfuric acid in aqueous acetone to form the /ran.v-decalin skeleton. Termination takes place by hydrolysis of the remaining cation syn to the adjacent bridgehead H-atom resulting in an equatorial position of the hydroxyl group45. 

The more energetic cis double bond in acyclic alkenes is epoxidized faster than the trans double bond.215 In contrast, opposite reactivity is observed for the stereoisomers of cycloalkenes, where the trans isomers are more reactive as a result of higher ring strain. This was demonstrated in the selective monoepoxidation of cis, trans-1,5-cyclodecadiene 235... 

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