Synthetic Studies toward Pseudolaric Acids:Radical Cyclization to Form Bridged Scaffold

Pseudolaric acids are a family of diterpenoid natural products that exhibit a broad spectrum of biological activities.The main structural feature of their framework is a trans-fused perhydroazulene bearing a bridged lactone positioned at the junction of the rings.Herein,we have developed a radical cyclization strategy that allows flexible tuning of the cyclization process through diverse silicon substitutions on the substrates.This strategy can assist in constructing a series of skeletons with structural resemblance to pseudolaric acids and expedites the construction of the bridged lactone.Finally,it facilitates the synthesis of the entire skeletal structure of the pseudolaric acidfamily of natural products,excludingthe B-ringfunctionalization.