Asymmetric transfer hydrogenation of imines and iminiums catalyzed by a water-soluble catalyst in water

Wu, Jiashou; Wang, Fei; Ma, Yongxiang; Cui, Xin; Liu, Cun; Zhu, Jin; Deng, Jingen; Yu, Bo

doi:10.1039/b600496b

Cited by 194 publications

(78 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The use of Noyori's ligand renders the complexes highly insoluble in water, due to the presence of the lipophilic phenyl groups, although recently some water-soluble complexes have been synthesized. 21,29,30 In addition, the presence of two chiral centers, which provide the complexes with enantioselectivity, makes the acquisition of a pure enantiomer a challenging process. Given that enantioselectivity is not a requirement in NAD + /NADH catalysis, not having chiral centers offers an acceptable strategy.…”

Section: ■ Introductionmentioning

confidence: 99%

Improved Catalytic Activity of Ruthenium–Arene Complexes in the Reduction of NAD⁺

et al. 2012

View full text Add to dashboard Cite

A series of neutral Ru II half-sandwich complexes of the type [(η 6 -arene)Ru(N,N′)Cl] where the arene is para-cymene (p-cym), hexamethylbenzene (hmb), biphenyl (bip), or benzene (bn) and N,N′ is N-(2-aminoethyl)-4-(trifluoromethyl)benzenesulfonamide (TfEn), N-(2-aminoethyl)-4-toluenesulfonamide (TsEn), or N-(2-aminoethyl)-methylenesulfonamide (MsEn) were synthesized and characterized. X-ray crystal structures of [(p-cym) The coordination of formate and subsequent CO 2 elimination to generate the hydride were modeled computationally by density functional theory (DFT). CO 2 elimination occurs via a two-step process with the coordinated formate first twisting to present its hydrogen toward the metal center. The computed barriers for CO 2 release for arene = benzene follow the order MsEn > TsEn > TfEn, and for the MsEn system the barrier followed bn < hmb, both consistent with the observed rates. The effect of methanol on transfer hydrogenation rates in aqueous solution was investigated. A study of pH dependence of the reaction in D 2 O gave the optimum pH* as 7.2 with a TOF of 1.58 h −1 for 2. The series of compounds reported here show an improvement in the catalytic activity by an order of magnitude compared to the ethylenediamine analogues. ■ INTRODUCTIONThe coenzyme nicotinamide adenine dinucleotide (NAD + ) and its reduced form 1,4-NADH have crucial roles in many cellular metabolic processes such as regulation of energy metabolism, antioxidative function, DNA repair and transcription, immunological functions, and cell death. 1 The coenzymes are involved in many other processes, acting as substrates and cofactors for enzymes such as NAD + ligases, oxidoreductases, polymerases, and deacetylases involved in biosynthesis.The coenzymes NAD + /NADH have been studied intensively during the past few years. It has been demonstrated that changes in metabolism result in fluctuations in the ratio NAD + / NADH or, conversely, changes in the ratio can produce metabolic changes. 2 In some cases alterations in the cellular redox status have been shown to play an important role in cell death, and therefore the coenzymes have become possible drug targets for chronic or autoimmune diseases such as Parkinson's, hepatitis C, diabetic vascular dysfunction, hyperglycemia, and cancer. 3 The concentration of NAD + and the ratio NAD + /NADH have been shown to be very important for cancer cells. On the one hand, due to their active metabolism, cancer cells generate high levels of oxidizing species and, therefore, they are under constant oxidative stress. 4 This makes cancer cells more dependent on redox regulatory systems and more sensitive to variations in the NAD + /NADH ratio. On the other hand, NAD + is required as a substrate for many enzymatic reactions such as ADP-ribosylation, which is crucial for genome stability and DNA repair. 3 Due to the up-regulation of some enzymes required for the biosynthesis of NAD + in cancer cells, a

show abstract

Section: ■ Introductionmentioning

confidence: 99%

Improved Catalytic Activity of Ruthenium–Arene Complexes in the Reduction of NAD⁺

et al. 2012

View full text Add to dashboard Cite

show abstract

“…Zhu, and coworkers modified the Noyori system for asymmetric transfer hydrogenation in order to perform the reaction in water [177]. They designed 38 [178], a sulfonated version of Noyoris ligand 26 for use in aqueous solution ( Figure 6.5).…”

Section: Reducing the Environmental Impact Of The Reactionmentioning

confidence: 99%

“…Zhu and coworkers have applied asymmetric transfer hydrogenation to N-alkyl 3,4-dihydroisoquinolinium salts, producing two tertiary amines highly stereoselectively [177]. Working in aqueous solution, they used Noyoris chiral [((R,R)-26) RuCl(p-cymene)] complex as a catalyst, HCO 2 Na as a hydrogen source, and CTAB as a surfactant.…”

Section: Syntheses Using the Asymmetric Transfer Hydrogenation Of Imimentioning

confidence: 99%

Chiral Amines from Transition‐Metal‐Mediated Hydrogenation and Transfer Hydrogenation

Church¹,

Andersson²

2010

Chiral Amine Synthesis

View full text Add to dashboard Cite

This chapter focuses specifically on the synthesis of amines of the form HNR Ã R 1 , NR Ã R 1 R 2 , and HN(X)R Ã (R Ã ¼ chiral alkyl group; R 1 , R 2 ¼ alkyl or aryl groups; X ¼ heteroatom such as N, S, or P) via the asymmetric hydrogenation of imines, enamines, and iminiums. Thus, we will discuss the formation of amines that have (i) chirality a to the nitrogen, and (ii) no carbonyl group a to nitrogen. Many reported examples of this reaction use substrates with C¼N moieties in a ring, so cyclic amines will receive considerable attention. We will discuss in detail the formation of chiral amines using the asymmetric reduction of aza-aromatic substrates, which has been a popular topic in recent years, and will cover the use of N-carbonyl groups to facilitate this reaction. However, the hydrogenations of nonaromatic a,b-unsaturated amides will not be discussed. Though chiral amides (HN(R Ã )C(O)R 1 ) can be produced highly enantioselectively using these reactions, the sheer number of publications on the topic places it outside the scope of this chapter. These hydrogenations are, however, well covered in a number of existing books and review articles [1]. In addition, we will not cover the related process, reductive amination, which is discussed elsewhere in this book.6.2 Chiral Amines with a Disubstituted Nitrogen Atom, HNR Ã R 1 Direct Asymmetric Hydrogenation of Alkyl-and Aryl-Substituted IminesThough less developed than the analogous reductions of olefins and ketones, the iridium-catalyzed asymmetric hydrogenation of imines (especially N-benzyl and Naryl amines) has received considerable study. It has therefore been the subject of

show abstract

“…Examples of water soluble ruthenium-arene catalysts for TH of imines in aqueous phase with HCOONa are also known [28,29]. For cyclic imines hydrogenation, we also described an efficient system based on a heterogenized Ir(I) complex bearing PTA supported into an ion-exchange resin, using water and H2 pressure [30].…”

Section: Transfer Hydrogenation Of Cyclic Iminesmentioning

confidence: 99%

“…Among Ru catalysts described in the literature for this class of homogeneously catalyzed reaction, outstanding performances were obtained for example with Noyori's complex [RuCl(η 6 -p-cymene)(TsDPEN)] (TsDPEN=N-(p-toluene-sulfonyl)-1,2-diphenylethylenediamine), using a formic acid-triethylamine azeotropic mixture as reducing agent [26,27]. Examples of water soluble ruthenium-arene catalysts for TH of imines in aqueous phase with HCOONa are also known [28,29]. For cyclic imines hydrogenation, we also described an efficient system based on a heterogenized Ir(I) complex bearing PTA supported into an ion-exchange resin, using water and H 2 pressure [30].…”

Section: Transfer Hydrogenation Of Cyclic Iminesmentioning

confidence: 99%

Ruthenium(II)-Arene Complexes of the Water-Soluble Ligand CAP as Catalysts for Homogeneous Transfer Hydrogenations in Aqueous Phase

2018

View full text Add to dashboard Cite

Abstract:The neutral Ru(II) complex κP-[RuCl 2 (η 6 -p-cymene)(CAP)] (1), and the two ionic complexes κP-[RuCl(η 6 -p-cymene)(MeCN)(CAP)]PF 6 (2) and κP-[RuCl(η 6 -p-cymene)(CAP) 2 ]PF 6 (3), containing the water-soluble phosphine 1,4,7-triaza-9-phosphatricyclo[5.3.2.1]tridecane (CAP), were tested as catalysts for homogeneous hydrogenation of benzylidene acetone, selectively producing the saturated ketone as product. The catalytic tests were carried out in aqueous phase under transfer hydrogenation conditions, at mild temperatures using sodium formate as hydrogen source. Complex 3, which showed the highest stability under the reaction conditions applied, was also tested for C=N bond reduction from selected cyclic imines. Preliminary NMR studies run under pseudo-catalytic conditions starting from 3 showed the formation of κP-[RuH(η 6 -p-cymene)(CAP) 2 ]PF 6 (4) as the pivotal species in catalysis.

show abstract

Asymmetric transfer hydrogenation of imines and iminiums catalyzed by a water-soluble catalyst in water

Cited by 194 publications

References 42 publications

Improved Catalytic Activity of Ruthenium–Arene Complexes in the Reduction of NAD⁺

Improved Catalytic Activity of Ruthenium–Arene Complexes in the Reduction of NAD⁺

Chiral Amines from Transition‐Metal‐Mediated Hydrogenation and Transfer Hydrogenation

Ruthenium(II)-Arene Complexes of the Water-Soluble Ligand CAP as Catalysts for Homogeneous Transfer Hydrogenations in Aqueous Phase

Contact Info

Product

Resources

About

Asymmetric transfer hydrogenation of imines and iminiums catalyzed by a water-soluble catalyst in water

Cited by 194 publications

References 42 publications

Improved Catalytic Activity of Ruthenium–Arene Complexes in the Reduction of NAD+

Improved Catalytic Activity of Ruthenium–Arene Complexes in the Reduction of NAD+

Chiral Amines from Transition‐Metal‐Mediated Hydrogenation and Transfer Hydrogenation

Ruthenium(II)-Arene Complexes of the Water-Soluble Ligand CAP as Catalysts for Homogeneous Transfer Hydrogenations in Aqueous Phase

Contact Info

Product

Resources

About

Improved Catalytic Activity of Ruthenium–Arene Complexes in the Reduction of NAD⁺

Improved Catalytic Activity of Ruthenium–Arene Complexes in the Reduction of NAD⁺