Total syntheses of (±)-phomallenic acids B and C, potent FAS II inhibitors, have been achieved by a palladium-catalyzed coupling of propargylic tosylates and terminal alkynes. Attempts to find an enantiospecific coupling using optically active propargylic compounds resulted in racemization of the products.
alkynes - allene - coupling - palladium - phomallenic acid