کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
52456 | 46875 | 2007 | 6 صفحه PDF | دانلود رایگان |

The chiral (1R,2S)-(−)-2-amino-1,2-diphenylethanol and (1S,2R)-(+)-2-amino-1,2-diphenylethanol had been immobilized on the layered frame of zirconium phosphate to obtain zirconium phosphonates (1R,2S)-(−)-4a and (1S,2R)-(+)-4b. The enantioselective addition of Et2Zn to benzaldehyde using zirconium phosphonates (1R,2S)-(−)-4a and (1S,2R)-(+)-4b as heterogeneous catalysts yielded secondary alcohol in 80.1% yield and e.e. values of up to 54.3%, which was only 7.6% e.e. lower than that using the corresponding ligands (1R,2S)-(−)-2a and (1S,2R)-(+)-2b as homogeneous catalysts. The zirconium phosphonates (1R,2S)-(−)-4a and (1S,2R)-(+)-4b were characterized by IR, SEM, XRD and TG analysis. SEM and XRD data showed that the catalysts (1S,2R)-(+)-4b and (1R,2S)-(−)-4a were in aggregate and mesopore structure with the same interlayer spacing 2.48 nm and pore diameter 5.6 nm.
Journal: Catalysis Communications - Volume 8, Issue 12, December 2007, Pages 1923–1928