In conclusion, a general method for obtaining α-diazoacetoacetic esters using 2-diazoacetoacetic acid (4) has been described. The latter reagent is readily generated, and can be synthesized on reasonable scale (ca. 5.0 mmol) in a straightforward manner from available starting materials. Coupling with acid 4 offers several advantages over known methods. Mainly, it allows diazo incorporation under neutral conditions into base-sensitive substrates that could not ...