Highly efficient and selective olefination of acyl phosphonates with ethyl diazoacetate catalyzed by a cobalt(II) porphyrin complex

The cobalt(II) porphyrin complex (CoTPP) was found to be an efficient catalyst for the Wittig type olefination of acyl phosphonates with ethyl diazoacetate (EDA) in the presence of triphenylphosphine (Ph₃P). By using this one pot methodology under mild conditions, densely functionalized vinyl phosphonates were obtained in high yields and high E/Z selectivities in relatively short reaction times. A rather broad substrate spectrum and steric influence on the reaction rate were observed.