The newly isolated bacterial FAS II inhibitor phomallenic acid C (3) was synthesized for the first timeas a 16:1 mixture of the (R)- and (S)-isomer with the diyne-allene motif constructed using a couplingunder Negishi conditions. By comparison with the synthetic sample, the natural phomallenic acid C wasestimated to be a 3.8:1 mixture of (R)-/(S)-isomers. This synthesis describes a new synthetic entry tooptically active allene diynes.