General Method for the Preparation of Indole-2-Weinreb Amides

Indole-2-Weinreb amides are obtained via thermolysis of α-azidocinnamic acid Weinreb amides in a Hemetsberger–Knittel-type cyclization. The required vinyl azides are not accessible by Knoevenagel condensation, but are obtained by cerium(IV)-mediated oxidative azidation of the corresponding cinnamic Weinreb amides.