Synthesis of Highly Substituted 2<i>H</i>‐Azirine‐2‐carboxylates via 3‐Azido‐4‐oxobut‐2‐enoates

Abstract

Abstract Phenacyl azides have been transformed into ethyl 4‐aryl‐3‐azido‐2‐methyl‐4‐oxobut‐2‐enoates by base‐induced coupling of the starting α‐azido ketone with ethyl pyruvate followed by elimination of methanesulfonic acid from the mesylate generated in situ from the labile aldol‐type intermediates ethyl 4‐aryl‐3‐azido‐2‐hydroxy‐2‐methyl‐4‐oxobutanoates. Thermolysis of ethyl 4‐aryl‐3‐azido‐2‐methyl‐4‐oxobut‐2‐enoates resulted in the formation of the hitherto unknown 3‐aroyl‐2‐ethoxycarbonyl‐2‐methyl‐2 H ‐azirines.(© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2008)