制备了一类新型的具有D 2-对称联苯骨架的对映体双桥联苯二亚磷酰胺,并将其用作手性配体,用格氏试剂在铜催化的烯丙基烷基化反应中使用。烷基化产物以定量产率获得,具有高达S N 2'/ S N 2之比的94:6的高区域选择性,并且对于S N 2'产物,对映体过量高达91.1%。独特的D 2-对称主链配体的优点是易于制备,并且其关键中间体可以从不希望的异构体中充分利用。
A series of new pyrrole-based tetraphosphorus ligands were synthesized and used for Rh-catalyzed isomerization-hydroformylation of internal olefins. It was found that the substituents at the 3,3',5,5'-positions of the biphenyl greatly effected the linear selectivity, and the alkyl-substituted tetraphosphorus ligands gave the best results (for 2-octene, n: i up to 207, for 2-hexene, n: i up to 362)
Atropos phosphoramidites with the D-2-symmetric biphenyl backbone were diastereoselectively prepared with ease from achiral tetrahydroxy biphenyls. This type of ligands is proved to be highly efficient in the Cu-catalyzed conjugate additions of diethylzinc to alpha,beta-unsaturated ketones and nitroalkenes. The unique D-2-symmetric backbone endows the ligands with an excellent chiral environment. (C) 2010 Elsevier Ltd. All rights reserved.
Highly enantioselective copper-catalyzed allylic alkylation with atropos phosphoramidites bearing a D2-symmetric biphenyl backbone
biphenyl phosphoramidites bearing a D2-symmetric biphenyl backbone was prepared and applied as chiral ligands in the copper-catalyzedallylicalkylation with Grignard reagent. The alkylation products were obtained in quantitative yields with high regioselectivities up to 94:6 of SN2′/SN2 ratio and enantiomeric excesses up to 91.1% for SN2′ products. The unique D2-symmetric backbone ligands have the
制备了一类新型的具有D 2-对称联苯骨架的对映体双桥联苯二亚磷酰胺,并将其用作手性配体,用格氏试剂在铜催化的烯丙基烷基化反应中使用。烷基化产物以定量产率获得,具有高达S N 2'/ S N 2之比的94:6的高区域选择性,并且对于S N 2'产物,对映体过量高达91.1%。独特的D 2-对称主链配体的优点是易于制备,并且其关键中间体可以从不希望的异构体中充分利用。
New tetraphosphite ligands for regioselective linear hydroformylation of terminal and internal olefins
tetraphosphite ligands L1–L5 and applied them to the rhodium-catalyzed hydroformylation of terminal and internal olefins. High catalytic reactivities and excellent regioselectivities for linear aldehydes were obtained in the rhodium-catalyzed hydroformylation of simple olefins (l/b ratio up to 90, 98.9% linear selectivity, 99.2% conversion) using the tetraphosphite ligand L2. And the tetraphosphite ligand L2 also