Axial [6,6′-(2,4-pentadioxy)]-1,1′-biphenyl-2,2′-diamine (PD-BIPHAM): practical synthesis and applications in asymmetric hydrogenation
摘要:
A rapid, reliable, and atom-economical procedure for the novel axially biphenyl diamine, (R,R,S-ax)-PD-BIPHAM 1, has been developed successfully by using highly efficient central-to-axial transformation strategy. The attractive feature of this methodology is that no tedious resolution was needed. The effectiveness of this new chiral skeleton was initially demonstrated by highly enantioselective hydrogenation of alpha-dehydroamino acid esters. (C) 2010 Elsevier Ltd. All rights reserved.
Axial Chirality Control by 2,4-Pentanediol for the Alternative Synthesis of C<sub>3</sub>*-TunePhos Chiral Diphosphine Ligands and Their Applications in Highly Enantioselective Ruthenium-Catalyzed Hydrogenation of β-Keto Esters
A highly efficient strategy for the synthesis of a series of C3*-TunePhos chiral diphosphine ligands was well established with several remarkable features. The synthetic utility of these ligands was explored for the ruthenium-catalyzed asymmetric hydrogenation of β-keto esters. Up to 99% ee values were achieved for the enantioselectivesynthesis of β-hydroxy acid derivatives, which are very important
Enantioselective Hydrogenation of α-Dehydroamino Acid Esters Catalyzed by Rhodium Complexes with Chiral Bisaminophosphine Ligands
作者:Xianfeng Sun、Wei Li、Le Zhou、Xumu Zhang
DOI:10.1002/adsc.201000038
日期:——
A highly efficient strategy for the synthesis of a series of chiral bisaminophosphine ligands was well established with several remarkable features. The synthetic utility of these ligands was explored for rhodium‐catalyzed asymmetric hydrogenations of α‐dehydroamino acidesters. Up to 98% ee values were achieved for the enantioselectivesynthesis of aminocarboxylic acids and their derivatives, which