Synthesis of chiral 4,4′-disubstituted 1,1′-spirobiindane-7,7′-diols and related phosphoramidites: the substituent effect of SIPHOS ligands in Rh-catalyzed asymmetric hydrogenation
作者:Shou-Fei Zhu、Yu Fu、Jian-Hua Xie、Bin Liu、Liang Xing、Qi-Lin Zhou
DOI:10.1016/j.tetasy.2003.08.017
日期:2003.10
Three chiral 4,4′-substituted 1,1′-spirobiindane-7,7′-diols and related monodentate spiro phosphoramidite ligands have been readily synthesized from enantiomerically pure 1,1′-spirobiindane-7,7′-diol. Excellent enantioselectivities were obtained with these new ligands in the rhodium-catalyzed asymmetric hydrogenation of dehydroamino acid derivatives and enamides. Comparing SIPHOS, ligands 4,4′-dibromo-SIPHOS
从对映体纯的1,1'-螺双茚满-7,7'-二醇容易地合成了三个手性4,4'-取代的1,1'-螺双茚满-7,7'-二醇和相关的单齿螺亚磷酰胺配体。这些新的配体在铑催化的脱氢氨基酸衍生物和酰胺的不对称加氢反应中获得了优异的对映选择性。与SIPHOS相比,配体4,4'-二溴-SIPHOS和4,4'-二苯基-SIPHOS具有相似的高对映选择性,尽管酰胺的氢化速率稍慢。配体的4,4'-位上的甲氧基取代基略微降低了氢化反应的对映选择性。