The pyroglutamic acid moiety is found in such natural products as lactacystin, 1 salinosporamide A, 2 dysibetaine, 3 and oxazolomycin 4 and is a common building block in asymmetric synthesis. 5 Despite their abundance in nature, there is no straightforward general synthesis available for this simple framework. The Ugi 4-center-3-component reaction (U4C-3CR) 6 of γ-ketoacids, [RCO(CH 2 ) 2 CO 2 H], provides ready access to the carbon framework of ...
