Synthetic Studies on Natural Products Possessing Picrotoxane Carbon Skeleton

Abstract

Synthetic investigation on physiologically active natural products having picrotoxinin type (picrotoxane) sesquiterpenoids and terpene alkaloids is reviewed. Terpene alkaloid, dendrobine has been synthesized successfully by four groups in a racemic form. From a synthetic standpoint, the more challenging and complex target was the sesquiterpenoid of this class and total syntheses of picrotoxinin, coriamyrtin and tutin have been accomplished in these five years. Of these synthetic works picrotoxinin has been synthesized from (-)-carvone in twenty steps and coriamyrtin from protoanemonin in fifteen steps utilizing the efficient, beautiful and stereocontrolled synthetic strategies. Total syntheses of these terpenoids have been also achieved by using isotwistane compound as a common intermediate. Synthetic approach to the above natural products is also briefly described.