Synthesis of ferrocene-containing six-membered cyclic ureas via alpha-ferrocenyl carbocations

A series of ferrocene-containing six-membered cyclic ureas (1-aryl-4-ferrocenyl-3-phenyltetrahydropyrimidin-2(1H)-ones) was synthesized (in high-to-excellent yields) by reacting the corresponding amino-propanols with phenyl isocyanate and the subsequent intramolecular cyclization of the thus obtained beta-hydroxy ureas (prompted by acetic acid), via an alpha-ferrocenyl carbocation