PALLADIUM-II PROMOTED REARRANGEMENT OF GERMACRANOLIDES - SYNTHESIS OF(-STOEBENOLIDE AND (+)-DEHYDROMELITENSIN())

Catalytic amounts of bis(benzonitrile)palladium (II) chloride enhanced reaction rates of germacranolides Cope rearrangement to elemanolides. On the other hand, equimolecular amounts of the palladium complex tra nsformed germacranolides into eudesmanolides. These phenomena provide a versatile procedure for the synthesis of eudesmanolides and elemanol ides under relatively mild experimental conditions. Thus, (+)-stoebeno lide and (+)-dehydromelitensin were alternatively synthesized starting out from (+)-salonitenolide. (C) 1998 Elsevier Science Ltd. All right s reserved.