Improved Arndt−Eistert Synthesis of α-Diazoketones Requiring Minimal Diazomethane in the Presence of Calcium Oxide as Acid Scavenger

Abstract

A practical methodology to obtain alpha-diazoketones through an improved Arndt-Eistert synthesis is described. The method allows the efficient transformation of acid halides using a stoichiometric amount of diazomethane in the presence of calcium oxide, without concomitant ketene or haloketone formation. The obtained alpha'-brominated-alpha-diazoketones were employed as suitable substrates for the synthesis of interesting alpha-arylamino-alpha'-halomethylketones.