Toward a Total Synthesis of Divergolide A; Synthesis of the Amido Hydroquinone Core and the C10-C15 Fragment

A ring-closing metathesis (RCM) approach was envisioned for installing the E double bond at the C9 and C10 positions of divergolide A, isolated from a mangrove endophyte. Accordingly, the C10-C15 diene diol fragment and the amido hydroquinone core with the requisite functionalities and stereochemistry have been synthesized by using the norephedrine-based syn-selective glycolate aldol and the anti-selective aldol reactions, respectively. CuI-catalyzed amidation was employed to access the anilide intermediate, which was further transformed into the amido hydroquinone core.