Total synthesis of yersiniabactin, a siderophore from cultures of the bacterium Yersinia enterocolitica, was accomplished. Chirality at the readily racemizable C-9 carbon was preserved during cyclization of b-hydroxythioamide by means of Burgess reagent leading to thiazoline. Based on its synthesis, the absolute con®guration of natural yersiniabactin has been determined as 9R, 10RS, 12R, 13S and 19S. q 2001 Elsevier Science Ltd. All rights reserved.