A systematic study of the Suzuki-Miyaura cross-coupling
reaction of thiazoleboronic esters under microwave conditions is
presented. Boronic acid esters were prepared in the 4- and 5-position
of the thiazole ring and subsequently cross-coupled with a number
of different (hetero)aryl halides. Yields of the coupling process
depended on the reactivity of the boronic acid at the particular position
in the thiazole system, as hydrolysis and subsequent deboronation
was found to be a major side reaction.
cross-coupling - homogeneous catalysis - heterocycles - palladium - lithiation