The benzofuranone-indolyloxazole fragment of the polycyclic marine natural product diazonamide A was prepared from tryptamine. The oxazole ring was synthesized from an α keto-indole via cyclodehydration with Ph 3P Cl 3CCCl 3, and after selective Stille biaryl coupling with 2-iodo-6-stannylphenol, the benzofuranone ring was constructed by an intramolecular Heck annulation of an α, β-unsaturated aryl ester.