Enantioselective terpene synthesis based on R-(+)-limonene

The prevalence of a C12 - common core in diverse C15-C30 terpenes has been recognised. A bifun%onal C 12-cyclopentanoid derive 5 corresponding to this common-core has been prepared from R-(+)-limonene. The enantiomerically pure 5 has been elaborated to several sesqui- and diterpene skeleta. In particular, enantioselective syntheses of isodaucane sesquiterpene, (+)-aphanamol- I, 3 and a dolabellane diterpene, 6-araneosene 26 have been accomplished for the first time. A general solution to the stereochemical problem associated with this class of compounds has been devised. Syntheses of (-)- daucene 8 and (+)-isoamijiol 17 are also described