Total synthesis of aculeatins A and B from L-malic acid

An efficient total synthesis of the cytotoxic spiroketal natural products aculeatin A and B is described. The synthesis of the 1,3,5-triol moiety with appropriate configuration was accomplished from the commercially available L-malic acid. The key steps in this synthesis are the Barbier allylation, LiAlH4/LiI-mediated syn-stereoselective 1,3-asymmetric reduction, and phenyliodine bis(trifluoroacetate) (=[bis(trifluoroacetoxy)iodo]benzene; PIFA) mediated oxidative spirocyclization