SYNTHESIS AND ABSOLUTE-CONFIGURATION OF THE ANTIPARASITIC FURANOSESQUITERPENES (-)-FURODYSIN AND (-)-FURODYSININ - CAMPHOR AS A 6-MEMBERED RING CHIRAL POOL TEMPLATE

The syntheses of (-)-furodysin ((-)-2a) and (-)-furodysinin ((-)-3a) in four steps starting from (+)-9-bromocamphor (18) has been accomplished, thus establishing the absolute configuration of these and related metabolites. This was made possible by the unexpected exo selectivity in the aldol condensation of camphor-like enolates with aldehydes. This has been found to be a general phenomenon in the camphor system. Further, anionic fragmentation of the C1-C7 bond of camphor derivatives has allowed access to synthetic intermediates containing functionalized six-membered rings, thus opening up avenues from camphor to a new class of chiral pool elements not currently available from chiral pool substances.