A Concise Formal Synthesis of Diazonamide A by the Stereoselective Construction of the C10 Quaternary Center

Abstract

Protecting groups are overrated! A formal total synthesis of diazonamide A is described. The key step in this synthesis is an intramolecular SNAr reaction between an oxindole and a bromooxazole. Interestingly, this reaction proceeds best using the mild base Na2CO3, and with no protecting groups on the oxindole nitrogen atom or phenol groups of the cyclization precursor.