Total synthesis of grayanane natural products.

Grayananes are a broad family of diterpenoids found in plants, comprising more than 160 natural products. Most of them exhibit interesting biological activities, often representative of use in traditional medicine. Over the last 50 years, various strategies were described for the total synthesis of these diterpenoids. In this review, we survey the literature for synthetic approaches to access grayanane natural products. We will focus mainly on completed total syntheses, but will also mention unfinished synthetic efforts. This work aims at providing a critical perspective on grayanane synthesis, highlighting the advantages and downsides of each strategy, as well as the challenges remaining to be tackled.