Studies on the coupling of substituted 2-amino-1,3-oxazoles with chloro-heterocycles

Direct coupling of five-membered heterocyclic amines with halo-heterocycles is a notoriously recalcitrant transformation. Herein we report our findings on the coupling of substituted 2-amino-1,3-oxazoles with chloro-heterocycles. Whereas the coupling of 2-amino-1,3-oxazole is inefficient under a large variety of state-of-the-art catalytic conditions tested, coupling of an ester substituted 2-amino-1,3-oxazole is relatively efficient and provides access, via a hydrolysis–decarboxylation protocol, to the 2-amino-1,3-oxazole coupled products.