Biosynthesis of Sesquiterpene Picrotoxanes

At this time, the postulated precursor copabomeol (474) was isolated as the main sesquiterpene from Finns sylvestris and thus became available. 

Finally, Jommi et al. addressed the question of the hydrogen shift following the ring closure of famesyl diphosphate to the cyclodecadiene within the biosynthesis of tutin (11) (232). 

Although investigations of biosynthesis have become considerably more convenient by shifting to stable isotopes and nondestructive spectroscopic methods, the pioneering work was never continued. Thus, the pathway from copabomeol (474) to dendrobine (82), mono- and dilactone picrotoxanes, and norditerpene picrotox-anes is stiU unknown and no enzymes of this biosynthetic pathway have been defined or isolated. There is mention of genes of the dendrobine bios3mthesis isolated and expressed in Escherichia coli (233). 

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