Acid-promoted olefination of ketones by an iron(III) porphyrin complex.

[reaction: see text] The acid-promoted olefination of unactivated ketones with diazo reagents in the presence of triphenylphosphine can be catalyzed by the commercially available iron(III) porphyrin complex Fe(TPP)Cl. The reactions were effectively carried out under mild conditions in a one-pot fashion with the use of a stoichiometric diazo reagents and substoichiometric benzoic acid. Examples include aromatic, aliphatic, cyclic, and unsaturated ketones with ethyl diazoacetate or tert-butyl diazoacetate.