Total syntheses of the strobilurins G, M, and N

The key reactions in the general synthesis of strobilurins are the highly (Z)-selective Wittig reaction of an (E)-cinnamaldehyde with the phosphorus ylide derived from (1,1-dibromoethyl)triphenylphosphonium bromide, followed by bromine–iodine exchange and Pd–Cu co-catalyzed Stille cross-coupling of the resulting alkenyl iodide with methyl (Z)-2-tributylstannyl-3-methoxyacrylate (). The synthetic strobilurins G, M, and N were identical with the corresponding natural compounds. In addition, the (2′ S)-configuration of strobilurin G () was unambiguously established by oxidative degradation of the synthetic intermediate to (R)-2,3-dihydroxyisovaleric acid.