Tricyclo 9.3.0.01 tetradecane

Barriault developed a new pericyclic domino process for the synthesis of the bioactive diterpenoid vinigrol (4-262), which was isolated from Vtrgaria nigra [92]. The natural product possesses antihypertensive and anti-platelet-aggregating properties. 4-262 contains a unique tricyclo [4.4.4.04a8a]tetradecane framework, which could be obtained by a combination of an oxy-Cope, a Claisen and an ene reaction... 

Many bridged ring systems are named by the von Baeyer system. Von Baeyer names are used mostly for bridged ring systems and occasionally for nonbridged ring systems. Examples of von Baeyer names are bicyclo[3.2.1]octane and tricyclo[7.4.1.0 ]tetradecane. 

A different mechanism has been proposed to explain the simultaneous presence of cyclobutenebriarein A and one or more of its possible precursors in Briareum asbestinum from the Bahamas. This derivative is the first known example of a natural substance containing the tricyclo [8,4,0,0 ]tetradecane system. 

A few other tricyclic diterpenes have been isolated, almost all of them from species of Sinularia, a genus that is an excephonal source of sesqui- and diterpenes. The following three examples are nor-diterpenes. Yonarolide and scabrohdes A and B seem to be the only natural representatives of this tricyclo[7,5,0,0 ]tetradecane, and the name yonarane has been proposed for this new carbon skeleton. Ineleganolide and horiolide are two other examples of nor-diterpenic lactones with an original carbon skeleton. 

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