SYNTHESIS OF 2-ARYLBENZOXAZOLES VIA THE PALLADIUM-CATALYZED CARBONYLATION AND CONDENSATION OF AROMATIC HALIDES AND ORTHO-AMINOPHENOLS

A new synthetic method is reported in which 2-arylbenzoxazoles can be prepared by the palladium-catalyzed condensation of aryl halides with o-aminophenols followed by dehydrative cyclization. This method is tolerant of a wide variety of functional groups on either aromatic ring and gives good to excellent yields of products. An aliphatic vicinal amino alcohol gave a bis-acylated product as well as a chlorine-containing product with only a small amount of the desired 2-aryloxazole being formed. Methyl iodide and benzyl bromide gave only alkylated products.