Copper- and palladium-catalyzed intramolecular C-S bond formation: a convenient synthesis of 2-aminobenzothiazoles

Copper- and palladium-catalyzed intramolecular C-S bond formation by cross-coupling between an aryl halide and thiourea functionality is demonstrated for the synthesis of 2-aminobenzothiazoles, wherein the Cu-catalyzed protocol is generally superior and more cost effective than the Pd-catalyzed protocol; the Cu-catalyzed reaction also further expands recent studies exploring the utility of Cu salts as replacements for Pd in carbon-heteroatom bond-forming reactions. A one-pot variant combining the synthesis of the thiourea and the cyclization was also demonstrated.