Inorganic-organic hybrid double sulfates as catalysts of the diastereoselective nitroaldol reaction

Abstract : Bis(1-phenylethanaminium) disulfatotetraaquazincate(II) dihydrate (C8H12N)2[Zn(H2O)4(SO4)2]*2H2O (1), bis(1H-benzo[d]imidazolium) hexaaquazinc(II) bis(sulfate) tetrahydrate (C7H7N2)2[Zn(H2O)6](SO4)2*4H2O (2) and bis(2-methyl-1H-imidazolium) hexaaquazinc(II) bis(sulfate) dihydrate (C4H7N2)2[Zn(H2O)6](SO4)2*2H2O (3) have been synthesized and fully structurally characterized including single-crystal X-ray diffraction analysis. 1-3 are organically templated hybrid layered materials comprising aquazinc(II) and aminium cations and sulfate anions. 1-3 are effective catalysts in the asymmetric Henry reaction; 1 being the most efficient one (yields up to 85% and threo/erythro diastereoselectivity up to 89:11).