Determination of the Absolute Configuration of a Series of Halogenated Furanones from the marine alga delisea pulchra

The absolute configuration of a series of naturally occurring and semi-synthetic halogenated furanones is proposed on the basis of chemical interconversions and X-ray and CD analyses. The CD analyses clearly reveal that the presence of the allylic O-atom has a strong influence in determining the sign and intensity of the low energy π→π* transition.