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Ohkuma, Takeshi; Takeno, Hiroshi; Honda, Yoshiyuki; Noyori, Ryoji

doi:10.1002/1615-4169(20010430)343:1<369::aid-adsc369>3.3.co;2-y

Cited by 32 publications

(39 citation statements)

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“…The polystyrene-bound BINAP/DPEN-Ru complex (beads) in the presence of (CH 3 ) 3 COK catalyzes the hydrogenation of 1'-acetonaphthone with an SCR of 12 300 in a 2-propanol-DMF mixture (1 : 1, v/v) to afford the chiral alcohol in 97% ee (Fig. 32.35) [113]. This supported complex is separable by a simple filtration, and is reusable as a catalyst.…”

Section: Alkyl Aryl Ketonesmentioning

confidence: 89%

Enantioselective Ketone and β‐Keto Ester Hydrogenations (Including Mechanisms)

Ohkuma¹,

Noyori²

2006

The Handbook of Homogeneous Hydrogenation

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Enantioselective hydrogenation of b-keto esters is a well-established procedure to produce chiral b-hydroxy esters in high optical purity [1][2][3][4]. Many important biologically active compounds have been synthesized through this procedure, even on a commercial scale [1][2][3][4]. Ru complexes [5] bearing appropriate chiral phosphine ligands [6][7][8] provide excellent catalytic efficiency for this reaction. Certain chiral Rh catalysts [3,4] and heterogeneous Ni catalysts [9] are also utilized. The recent development of the chiral diphosphine/diamine-Ru catalyst enables rapid and stereoselective hydrogenation of simple ketones without a hetero-atom functionality close to the carbonyl group [2,4]. These enantioselective transformations are summarized in the present chapter. Chiral LigandsIn enantioselective hydrogenation of ketonic substrates, the excellent catalytic performance such as high turnover number (TON), turnover frequency (TOF = -TON h -1 or s -1 ), and enantioselectivity is achievable only when (pre)catalysts are prepared by the appropriate combination of metal species and chiral ligands [6-8, 10, 11]. Stereo-repulsive interaction between substituents of ligands and substrates is normally utilized for the regulation of stereochemistry. The metal and ligand must be carefully selected because of the diversity of substrate structures [1][2][3][4][5]. Chiral diphosphine ligands with a C 2 symmetry (see Fig. 32.1) have played a main role in this respect. Recently, however, various effective C 1 phosphine ligands as well as phosphinite ligands have been developed, the structures of which are illustrated in Figures 32.2 and 32.3, respectively. Chiral amine and imine ligands (Fig. 32.4) are also useful, particularly when they are coupled with a chiral diphosphine ligand in the hydrogenation of simple ketones [2,4,5]. Immobilized BINAPs are detailed in Figure 32.5.

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Section: Alkyl Aryl Ketonesmentioning

confidence: 89%

Enantioselective Ketone and β‐Keto Ester Hydrogenations (Including Mechanisms)

Ohkuma¹,

Noyori²

2006

The Handbook of Homogeneous Hydrogenation

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“…The highest TON×s/TOF×s reported in the literature for covalently attached diphosphine catalysts are in the range of 10,000/2000 h À1 for Rh [1,6] and of 33,000/400 h À1 for Ru. [7] Nevertheless, compared to the very active soluble catalysts, the TOF×s for the heterogenized analogs are lower by a factor of 2 ± 5 while the enantioselectivities are only slightly affected. The influence of immobilization on activity and productivity becomes more pronounced with increasing s/c ratio as illustrated by entries 2.1 and 2.6.…”

Section: Discussionmentioning

confidence: 99%

More than 100,000 Turnovers with Immobilized Ir-Diphosphine Catalysts in an Enantioselective Imine Hydrogenation

Pugin¹,

Landert²,

Spindler³

et al. 2002

Advanced Synthesis & Catalysis

100

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“…Hydrogenation of 1-hydroxy-2-propanone, a simple aliphatic hydroxy ketone, gave 1,2-propanediol in 80% ee.32,34 6. Application to the Synthesis of Biologically Active…”

Section: Beyond the Border Between Hydrogenation Andmentioning

confidence: 99%