Noyori’s catalyst

Another interesting example is the supportation of Noyori s catalyst family containing Ru-chiral BINAP and chiral 1,2-diphenylethylenediamine [96]. These catalysts are suitable for the enantioselective hydrogenation of a variety of sub-... 

Fig. 42.12 I immobilization of Noyori s catalyst components on functionalized polystyrene.

Vedejs et al. reported catalyst inhibition during a study on the enantioselective transfer hydrogenation of dihydro-isoquinolines using Noyori s catalyst (Scheme 44.2) [27]. Here, the problem is caused by the bidentate nature of the substrate. Whereas the bromo compound 1 a could be rapidly reduced, the tosylamide-sub-stituted compound lb could not be reduced, and although the problem could be alleviated somewhat by alkylation of the sulfmamide to 1 c, hydrogenation of this was still sluggish. Although the authors propose this to be a case of product... 

Jiang et al.113 synthesized another tridentate ligand 121 for asymmetric transfer hydrogenation. Ru-121-catalyzed asymmetric transfer hydrogenation gives comparable enantioselectivity to Noyori s catalyst 109 but shows more... 

The highest ttn published to our knowledge so far for chemzymes (in the sense of polymer-enlarged chemical catalysts) is found in the transfer hydrogenation process catalyzed by Gao-Noyori s catalyst bound to a siloxane polymer (Fig. 3.1.3, 4) [13, 14]. In this transfer hydrogenation acetophenone is reduced to (S)-phenyl-ethanol using isopropanol as hydrogen donor. The product is produced in a CMR with 91% ee at a space-time yield of 578 g L d the ttn for the catalyst is 2633. 

Scheme 9.11 Programmed assembly of MOCP 18 for immobilization of Noyori s catalyst and the enantioselective hydrogenations of ketones.

In 2003, Henschke and coworkers described asymmetric hydrogenation of 2 methylquinoxaline with Noyori s catalyst RuCl2(diphosphine)(diamine). In most case, moderate enantioselectivities and excellent conversions were obtained within 20h with S/C 1000/1 [45]. The combination of Xyl HexaPHEMP and (S,S) DACH afforded the best enantioselectivity (73% ee) with full conversion. 

In 2005, M. Wills and coworkers reported the synthesis of a Ru(II) tethered version of Noyori s catalysts 3.28 (Figure 3.10). These complexes have a rigid stmcture and are stereochemically well defined moreover they are very active catalysts for asymmetric hydrogenation of ketones. 

Scheme 5 Noyori s catalyst for asymmetric hydrogen transfer reaction of ketones...

Figure 15.13. Noyori s catalyst for the hydrogenation of unfunctionalized ketones.

On the other hand, Backvall, Privalov and co-workers proposed an inner-sphere reaction mechanism based on experimental studies and DFT calculations for the reduction of imines with Shvo s catalyst (370,371). The same group demonstrated that imines have to be protonated before being reduced by ruthenium Noyori s catalyst (372). But kinetic studies on the reduction of cyclic imine I (Fig. 94) reported by Blackmond and coworkers (373) conclude that the un-protonated imine is reduced by a Rh(III) catalyst of the Noyori-type catalyst (Fig. 95), using formic acid as the hydrogen transfer agent. 

Duilio Arigoni I would say yes, if the definition is man-made catalysts. Thus the Pfaltz compounds are chemzymes and Noyori s catalysts are chemzymes. 

Hartmann, R. Ghen, P. Numerical modeling of differential kinetics in the asymmetric hydrogenation of acetophenone by Noyori s catalyst. Adv. Synth. 

Marks showed in the 1990s that the cyclohydroamination of alkenes was catalyzed by organolanthanide complexes and, in 2000, Hartwig reported the enantioselective hydroamination of p-trifluromethylstyrene by aniline using Noyori s catalyst [R-BINAP-Pd(0S02CF3)2] (toluene, 45°C, 81% yield, 81% ee). 

Enantioselective olefin hydroamination with aniline is catalyzed by Noyori s catalyst, and hydroamination of internal alkynes with primary amines is catalyzed by Cp2TiMc2. 

The pivotal dibromide was synthesized from acetyl acetone (198). An established protocol for chlorination at both methyl groups was followed by an anh-selective reduction of the diketone with Noyori s catalyst. Treatment with KOH generated the bis-epoxide, which was ring-opened with NajNiBr, which serves as an alternative to the Finkelstein... 

Oxidation of the hydro>yl group followed by the highly enantioselective asymmetric reduction of the resulting ketone (in the presence of the Noyori s catalyst 52) yielded alcohol (i )-54 (ee>96%). Subsequent... 

SCHEME 30.27. Catalytic asymmetric transfer hydrogenation with Noyori s catalyst as a key step in the total syntheses of diospongins A and B, eicosanoids, and synparvolides. 

In 2009, Srihari and group reported on stereoselective total synthesis of synparvolide B and pi-synparvolide A using Noyori s ATH of ketone as a key step. Synparvo-lides (synparvolide A, synparvolide B, and synparvolide C) were isolated from the leaves of Syncolostemon parviflorus, a medicinal plant that is used as an emetic to treat loss of appetite. " Stereoselective reduction of the ketone 141 was accomplished with (5,5)-Noyori s catalyst in i-PrOH to give l,3-fl ti-isomer in 86% yield. 

A new approach to the C(7)-C(13)-intermediate for the synthesis of phoslactomycin B, a potent selective PP2A inhibitor, was developed by Kobayashi et al. ° For the construction of the C(ll)-stereocenter, the asymmetric transfer hydrogenation with Noyori s catalyst has been used. Diastereomers, obtained with a ratio 1 17, was easily... 

Lee, Yun-Choi, et al. described the synthesis of optically active tetrahydroisoquinoline alkaloids, (R)-(+)-higen-amine, (5)-(—)-higenamine, and their optically active 1-naphthylmethyl analogs, via enantioselective hydrogenation of the dihydroisoquinoline intermediates 212 as a key step. Catalytic asymmetric reduction of imine was accomplished with Noyori s catalyst RuCl[(5, 5)-TsDPEN... 

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