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

✍ Scribed by Gabriele M. König; Anthony D. Wright; Gérald Bernardinelli

• Publisher: John Wiley and Sons
• Year: 1995
• Tongue: German
• Weight: 339 KB
• Volume: 78
• Category: Article
• ISSN: 0018-019X
• DOI: 10.1002/hlca.19950780320

✦ Synopsis

quai Ernest-Ansermet, CH-I 2 1 1 Geneva 4 (20.111.95) 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 0-atom has a strong influence in determining the sign and intensity of the low energy rr +rr* transition.

Introduction. -Recently, the planar structures for a group of naturally occurring polyhalogenated furanones, derived from the temperate marine red alga Delisea pulchra (cf. Jmhriata) [I], were reported [2]. In this report, the configuration for the new compounds was not proposed, as there were no possibilities to relate the chiral centers of these molecules. Since this report, one of the compounds, 1, crystallized. X-Ray analysis of 1 led to the determination of its absolute configuration. From this result, it was considered likely that the absolute configurations for all of the natural products reported previously [2] could be proposed on the basis of chemical interconversions and CD analyses. The X-ray analysis, chemical interconversions and the CD analyses are the subject of the current report.