A series of monophosphite ligandsderivedfromcarbohydrates and H8-BINOL have been synthesized. Excellent enantioselectivities (over 99% ee) were obtained when these ligands were applied in the Rh-catalyzed asymmetrichydrogenation of dimethyl itaconate and enamides.
We synthesized a modularsugar-based phosphite ligandlibrary for the Ni-catalyzed trialkylaluminum addition to aldehydes. This library has been designed to rapidly screen the ligands to uncover their important structure features and determine the scope of the phosphite ligands in this catalytic reaction. After systematic variation of the sugar backbone, the substituents at the phosphite moieties,
我们合成了镍基催化的三烷基铝加成醛的模块化糖基亚磷酸酯配体库。该文库旨在快速筛选配体,以揭示其重要的结构特征,并确定该催化反应中亚磷酸酯配体的范围。在系统改变糖主链,亚磷酸酯部分的取代基和配体主链的柔韧性后,单亚磷酸酯配体1,2:5,6-二-O-异亚丙基-3- O -((3,3' ; 5,5'-四-叔丁基-1,1'-联苯-2,2'-二基)亚磷酸酯)-α- d -glucofuranose 1C被发现是最佳的,产生高活性和对映选择性(EE是给94%)的几种芳基醛。
Carbohydrate-derived monophosphite ligands for Rh-catalyzed enantioselective hydrogenation of α- and β-dehydroamino acid esters
A series of monophosphite ligands derived from D-fructose and D-glucose have been synthesized and employed in Rh-catalyzed asymmetric hydrogenation of alpha- and beta-dehydroamino acid esters. A variety or chiral alpha- and beta-amino acid esters have been obtained in excellent enantiomeric excess (LIP to 98.4% ee). (C) 2004 Elsevier Ltd. All rights reserved.