A synthetic approach to enfumafungin

The stereospecific synthesis of the dienophile subunit precursor D was achieved from the butenolide E. The ester corresponding to the precursor of A was obtained in 67% overall yield from the aldehyde C, via a chlorite oxidation and subsequent Mitsunobu reaction of the acid B with D. Tentative IMDA reactions of A did not presently afford the adduct (thermal or Lewis acid catalysis conditions).