Highly Enantioselective Pd-Catalyzed Asymmetric Hydrogenation of Activated Imines
作者:You-Qing Wang、Sheng-Mei Lu、Yong-Gui Zhou
DOI:10.1021/jo0700878
日期:2007.5.1
complexes are highly effective catalysts for asymmetrichydrogenation of activated imines in trifluoroethanol. The asymmetrichydrogenation of N-diphenylphosphinyl ketimines 3 with Pd(CF3CO2)/(S)-SegPhos indicated 87−99% ee, and N-tosylimines 5 could gave 88−97% ee with Pd(CF3CO2)/(S)-SynPhos as a catalyst. CyclicN-sulfonylimines 7 and 11 were hydrogenated to afford the useful chiral sultam derivatives in
Pd /双膦配合物是用于活化的亚胺在三氟乙醇中不对称氢化的高效催化剂。Pd(CF 3 CO 2)/(S)-SegPhos对N-二苯基亚膦酰基酮亚胺3的不对称氢化表明ee为87-99%,N- tosylimines 5与Pd(CF 3 CO 2)可以得到88-97%ee /(S)-SynPhos作为催化剂。环状N-磺酰亚胺7和11 进行氢化,以79-93%ee的比重得到有用的手性舒马坦衍生物,这是重要的有机合成中间体和农业和医药制剂的结构单元。
Multiple Dendritic Catalysts for Asymmetric Transfer Hydrogenation
作者:Ying-Chun Chen、Tong-Fei Wu、Jin-Gen Deng、Hui Liu、Xin Cui、Jin Zhu、Yao-Zhong Jiang、Michael C. K. Choi、Albert S. C. Chan
DOI:10.1021/jo0257795
日期:2002.7.1
and were well-characterized by NMR and MS techniques. Their ruthenium complexes prepared in situ had good solubility in the reaction medium (azeotrope of formic acid and triethylamine) and demonstrated high catalytic activity and enantioselectivity comparable to monomeric catalysts in the asymmetric transfer hydrogenation of ketones and imines. Quantitative yields and for some cases a slightly higher
'Salen' along: The iridium(III)–salen complex 1 efficiently catalyzes the title reaction of 2‐ethylbenzenesulfonyl azides to give five‐membered sultams with high enantioselectivity. Other 2‐alkyl‐substitued substrates lead to five‐ and six‐membered sultams with high enantioselectivity; the regioselectivity depends upon the substrate and the catalyst used. EDG=electron‐donating group.
Crosslinked polymers containing chiral N-sulfonylated diamine (TsDPEN) structure were synthesized by radical polymerization of chiral N1-(4-vinylbenzenesulfonyl)-1,2-diphenylethylene-1,2-diamine, divinylbenzene and achiral vinyl monomer. The polymer-immobilized chiral complex was prepared from the polymeric TsDPEN with ruthenium dichloride p-cymene. Asymmetric transfer hydrogenation of cyclic sulfonimine was performed using the polymer-immobilized TsDPEN-Ru (II) complex. The hydrophobic-hydrophilic balance of the polymers was tuned by means of the incorporation of the achiral vinyl monomers, which strongly influenced on the catalytic activity of the polymeric catalyst. In most cases the amphiphilic polymer-immobilized chiral catalysts are highly active in the asymmetric transfer hydrogenation. Enantioenriched sultam with up to 98% ee was obtained by using polymer-immobilized chiral catalysts containing quaternary ammonium salt in CH2Cl2. Some of the polymer-immobilized chiral catalysts containing quaternary ammonium salt were successfully used in water. Up to 95% ee was obtained by using the polymeric catalyst in water. Most of the quaternized polymeric catalysts showed sufficient reactivity and higher enantioselectivities compared with that of low-molecular-weight catalyst in water. (c) 2013 Elsevier B.V. All rights reserved.
A Chiral Rhodium Complex for Rapid Asymmetric Transfer Hydrogenation of Imines with High Enantioselectivity
作者:Jianmin Mao、David C. Baker
DOI:10.1021/ol990098q
日期:1999.9.1
[GRAPHICS]A chiral rhodium complex, (R)-Cp*RhCl[(1S,2S)-p-TsNCH(C6H5)CH(C6H5)NH2] (1a, (S,S)-Cp*RhCITsDPEN), generated from [Cp*RhCl2](2) and (1S,2S) N-p-toluenesulfonyl-1,2-diphenylethylenediamine [(S,S) TsDPEN], and its enantiomer 1b were found to provide superior catalysts for the rapid, high yielding, asymmetric transfer hydrogenation of some heterocyclic imines, using an HCO2H-Et3N azeotrope as the hydrogen source.