Heck reaction sesquiterpenes

Shibasaki has also reported impressive applications of the asymmetric intramolecular Heck reaction. For example, the Shibasaki group have applied their chemistry to the synthesis of compound 64, a key intermediate in the total synthesis of two complex triquinane sesquiterpenes 65 and 66, by making use of a Heck reaction/anion capture cascade sequence. ... 

SCHEME 13.4. An asymmetric Heck reaction in the total synthesis of the elemanolide sesquiterpene dilactone (- -)-vernoIepin 9. 

SCHEME 13.5. Application an asymmetric Heck reaction/anion-capture cascade process to the total synthesis of marine sesquiterpene capnellenols 14. 

In another example, Shibasaki and co-workers applied an asymmetric Heck reaction/anion-capture cascade process to the total synthesis of marine sesquiterpenes capnellenols 14 and capnellene 17 (Schemes 13.5 and 13.6). The cascade involved the use of prochiral cyclo-pentadienyl systems for the generation of bicyclic 71-allyl-palladium species, which were then trapped by a suitable nucleophile. Initial studies in the total synthesis of capnellenols described the trapping of the 71-allylpalladium... 

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