Sequential ring closure and [2,3]-sigmatropic rearrangement reactions: an approach to the synthesis of C-19 oxygenated cyathane-type diterpenoids
Abstract
Preparation of the tertiary allylic alcohols 17–22, follwed by subjection of these substances to the Still–Mitra [2,3]-sigmatropic rearrangement sequence, provides the functionalised bicyclo[4.3.0]nonanes 23–26; acquisition of 26; points to a strategy for the synthesis of C-19 oxygenated cyathane-type diterpenoids.