General routes to 4-methyl-2-substituted-furans: a total synthesis of pleraplysillin-2, a metabolite of the sponge, Pleraplysilla spinifera

A general approach to 4-methyl-2-substituted-furans is described in which 4-methyl-2-furyl-lithium is the key intermediate. Using this method, pleraplysillin-2, a sesquiterpenoid ester from the sponge Pleraplysilla spinifera, has been synthesised. An alternative, less efficient, route to this type of furan, via acyclic keto-epoxides, is also discussed.