Arylboronic Acid-Catalyzed Direct Condensation of Carboxylic Acids with Ureas

ABSTRACT The first example of the catalytic direct condensation of carboxylic acids with ureas to give N-acylureas, N,N′-diacyl-2-imidazolidones, and poly(N,N′-diacyl-2-imidazolidone)s is described. Arylboronic acids bearing electron-withdrawing substituents are highly effective as catalysts for this condensation. Furthermore, a new and efficient one-pot procedure for the conversion of carboxylic acids and urea to nitriles via N-acylurea intermediates was accomplished by using arylboronic acid and rhenium(VII) oxo complexes as hybrid catalysts.