화학공학소재연구정보센터
Catalysis Letters, Vol.118, No.3-4, 187-194, 2007
A novel type of chiral titanium phosphonates and hybrid titanium phosphonates for heterogeneous asymmetric catalysis
(1R, 2S)-(-)-2-amino-1, 2-diphenylethanol and (1S, 2R)-(+)-2-amino-1, 2-diphenylethanol had been immobilized on the layered titanium phosphonates 4a-d and hybrid titanium phosphonates 5a-c in spheroid form with interlayer space 20.845-19.407 angstrom which can be used as heterogeneous catalysts in the enantioseletive addition of diethylzinc to benzaldehyde to obtain optically active (R)-or (S)-1-phenylpropan-1-ol for the first time. It was shown that the titanium phosphonate 4a led to active heterogeneous catalysis for asymmetric additions of diethylzinc to benzaldehydes in 88.5% yield and ee value of up to 40.8% which decreased at 16% ee lower than corresponding chiral ligand in homogeneous asymmetric catalysis. AFM showed that the distribution of 1,2-dipenyl-2-aminoethanol organic moieties on the surface of titanium phosphonates irregularly lined like flow mark.