Total synthesis of twelve membered resorcyclic acid lactones, (R)-penicimenolide A, (R)-resorcyclide and (R)-dihydroresorcyclide

Abstract

Resorcyclic Acid Lactones or RALs are a class of fungal secondary polyketides isolated from a variety of fungal strains like Lasiodiplodia theobromae , Penicillium sp. , Syncephalastrum racemosum etc. This class of macrocyclic lactones are found to exhibit a broad spectrum of biological activities and are of significant synthetic importance. Herein, we report the first total synthesis of (R)-penicimenolide A, twelve membered RAL (RAL 12 ) isolated from Penicillium sp . (NO. SYP-F-7919). Besides, we also report the total synthesis of two other members, namely, ( R )- trans -resorcyclide and ( R )-dihydroresorcyclide. In the course of synthesis, we have utilized ring closing metathesis (RCM) as the key step in constructing the core macrolactone scaffold.