Novel rhodium-1,3-dialkyl-3,4,5,6-tetrahydropyrimidin-2-ylidene complexes as catalysts for arylation of aromatic aldehydes

Six new rhodium-tetrahydropyrimidin-2-ylidene complexes (2a–f) have been prepared and characterized by C, H, N analysis, 1H NMR and 13C NMR. Phenylboronic acid reacts with aldehydes in the presence of a catalytic amount of the new rhodium(I)-carbene complexes, RhCl(COD)(1,3-dialkyl-3,4,5,6-tetrahydropyrimidin-2-ylidene), (2a–f), to give the corresponding secondary aryl alcohols in good yields (72–96%).