Cycloisomerisation of modified terpenoid 1,6-enynes—synthesis of conformationally-restricted cyclic farnesyl analogues

The cycloisomerisation of various 1,6-enynes containing a modified terpenoid chain has been investigated to provide cyclopentanes with great potential as novel conformationally-restricted analogues of farnesyl diphosphate. The 4-diethylphosphono-ester substituent is shown to serve as a diastereocontrol element for the 1,6-enyne cycloisomerisation process.