Difluorocarbene transfer from a cobalt complex to an electron-deficient alkene.

We report the synthesis of the trifluoromethyl cobalt(iii)tetraphenylporphyrinato complex [Co(TPP)CF3], which loses fluoride upon one-electron reduction and transfers a difluorocarbene moiety to n-butyl acrylate to produce the corresponding gem-difluorocyclopropane. Catalytic CF2 transfer from Me3SiCF3 to n-butyl acrylate becomes possible when directly using the divalent cobalt(ii) porphyrin catalysts in the presence of NaI.