Oxidative cyclization reactions of trienes and dienynes: total synthesis of membrarollin

The regio- and stereoselective oxidative cyclization of trienes and dienynes containing one electron-deficient double bond in the presence of permanganate ion to yield 2,5-bis-hydroxyalkyltetrahydrofurans (THF diols) is described. The THF diols obtained might serve as convenient precursors to adjacent bis-THFs and the total synthesis of the Annonaceous acetogenin membrarollin.