Synthesis of Naphtho[2,3- d ]oxazoles via Ag(I) Acid-Mediated Oxazole-Benzannulation of ortho -Alkynylamidoarylketones.

A cascade oxazole-benzannulation for the synthesis of naphtho[2,3- d ]oxazoles has been developed employing ortho -alkynylamidoarylketones as substrates. This procedure provides the advantage of preparing a wide variety of substituents on naphtho[2,3- d ]oxazole structures. In addition, o -alkynylamidoarylketones could be prepared from easily accessible and a wide variety of commercially available starting materials. Therefore, this method is a judicious choice of strategy to synthesize naphtho[2,3- d ]oxazoles with a great variety of substituents. In this work, 27 examples were demonstrated to provide the desired products in moderate to good yields.