Enantiospecific construction of the carbon skeleton associated with manicol, an antineoplastic sesquiterpene from Dulacia guianensis (Olacaceae)

Reaction of (R)-perillaldehyde [(+)-3] with ylid 2 provided the annulated cyclohexenone 4 which was subjected to a Beckwith-Dowd ring-expansion sequence thereby affording cycloheptenone 7. Compound 7 embodies the full carbon skeleton associated with the sesquiterpene manicol (1) and possesses functionality such that it should be capable of elaboration to the natural product.