A short and efficient synthesis of chaetometlic acid A anhydride (2) is reported utilizing a doubly chemoselective cross coupling of myristyl cobaloxime with citraconic anhydride and diphenyl disulfide as the key step. Sulfide oxidation followed by syn elimination provides 2 in 64% overall yield starting from myristyl bromide. Basic hydrolysis of 2 is known to provide chaetomellic acid A dianion (3), the biologically active form.