Synthesis of enantiomerically pure perhydrofuro[2,3-b]furans.

Enantiomerically pure 2,5,6a-trisubstituted perhydrofuro[2,3-b]furans were obtained by cyclization of bis-alkenylketones, promoted by camphorselenenyl sulfate produced in situ by oxidation of camphor diselenide with ammonium persulfate in a mixture of water and acetonitrile at room temperature. The cyclization reaction proceeded through a double selenohydroxylation of the two double bonds and produced a mixture of the two diastereoisomers trans and cis 2,5-bis[(camphorseleno)methyl] perhydrofuro[2,3-b]furans. These were separated by medium pressure liquid chromatography and then deselenenylated with triphenyltin hydride and AIBN