Tandem palladium-catalyzed urea arylation-intramolecular ester amidation: regioselective synthesis of 3-alkylated 2,4-quinazolinediones.

o-Halo benzoates can be combined with monoalkyl ureas in a tandem palladium-catalyzed arylation-ester amidation sequence to deliver quinazolinedione products. The reactions are regioselective for formation of the 3-N-alkyl isomers. Significant variation of both coupling partners is possible, allowing the synthesis of a diverse array of substituted quinazolinediones, exemplified by the preparation of a simple unsymmetric-dialkylated natural product. [reaction: see text]