Efficient asymmetric hydrogenation of α-aminoacetophenone derivatives leading to practical synthesis of ()-(−)-levamisole

Takeda, Hideo; Tachinami, Takeshi; Aburatani, Masakazu; Takahashi, Hisashi; Morimoto, Toshiaki; Achiwa, Kazuo

doi:10.1016/s0040-4039(00)95203-1

Cited by 73 publications

(13 citation statements)

References 10 publications

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“…It has been demonstrated that other backbone-type ligands, BCPMs bearing both dissymmetrized phosphino groups, also show high enantioselectivity in similar rhodium-catalyzed asymmetric hydrogenation of various amino ketones. 12,13) In summary, we have described the synthesis of enantiopure biphenyl ligands bearing one or two diphenylphosphino group(s) and/or one or two dicyclohexylphosphino group(s), and their application to rhodium(I)-catalyzed asymmetric hydrogenation of itaconic acid and its analogs, (Z)-a-acetamidocinnamic acid, and 2-aminoacetophenone hydrochloride.…”

Section: Resultsmentioning

confidence: 99%

“…complexes as catalyst. We previously proposed a novel idea, "respective control concept" for designing new chiral ligands, 7-10) and developed efficient diphosphine ligands such as (2S-cis)-4-(dicyclohexylphosphino)-2-[(diphenylphosphino)methyl]-1-pyrrolidinecarboxylic acid 1,1-dimethylethyl ester (BCPM) and its analogs, 8,[11][12][13] (4R-trans)-[(2,2-dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene)]bis[bis(4-methoxy-3,5-dimethylphenyl)phosphine] (MOD-DIOP) and its analogs, [14][15][16][17] etc. (Fig.…”

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Preparation of Axially Chiral Biphenyl Diphosphine Ligands and Their Application in Asymmetric Hydrogenation

et al. 2004

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Development of efficient methods for catalytic enantioselective synthesis has been an important subject for the practical synthesis of optically active organic compounds.1) Numerous methods of enantioselective synthesis employing various catalysts such as transition metal complexes coordinated with many types of chiral ligands have been reported for more than three decades. [1][2][3][4][5][6] For the development of efficient chiral catalysts, creation of new types of ligands is a most significant strategy. Among various types of chiral ligands, diphosphines are the most effective and are widely applicable in the catalytic asymmetric hydrogenation of prochiral compounds such as olefins, ketones, and imines using transition metal (rhodium, ruthenium, iridium, etc.) complexes as catalyst. We previously proposed a novel idea, "respective control concept" for designing new chiral ligands, 7-10) and developed efficient diphosphine ligands such as (2S-cis)-4-(dicyclohexylphosphino)-2-[(diphenylphosphino)methyl]-1-pyrrolidinecarboxylic acid 1,1-dimethylethyl ester (BCPM) and its analogs, 8,[11][12][13] (4R-trans)-[(2,2-dimethyl-1,3-dioxolane-4,5-diyl)bis(methylene)]bis[bis(4-methoxy-3,5-dimethylphenyl)phosphine] (MOD-DIOP) and its analogs, [14][15][16][17] etc. (Fig. 1) for rhodium-catalyzed asymmetric hydrogenation of some prochiral ketones (ketopantolactone, a-and bamino ketones, etc.), and olefins (itaconic acid and its derivatives, N-acyldehydroamino acids, etc.). Furthermore, we revealed that phosphines bearing electron-donating groups such as cyclohexyl groups, p-(dimethylamino)phenyl groups, and p-methoxy-m,mЈ-dimethylphenyl groups enhance not only the catalytic activity but also the enantioselectivity in the rhodium-catalyzed hydrogenations. The p-methoxym,mЈ-dimethylphenyl (abbreviated to MOD) group was found to be a useful component for developing efficient ligands on the basis of its steric effect (m-Me) as well as its electronic effect (p-MeO, m-Me).15) We also reported in preliminary communications the design and preparation of axially chiral diphosphines, [18][19][20][21] which were found to be very efficient ligands for ruthenium-catalyzed asymmetric hydrogenation of a b-keto ester or rhodium-catalyzed asymmetric hydrogenation of an a-amino ketone. In this article we describe in detail the synthesis of optically pure 3,3Ј-dimethoxy-2,2Ј,4,4Ј-tetramethyl-1,1Ј-biphenyls 8a-c bearing one or two 6,(6Ј)-dicyclohexylphosphino group(s) and/or 6,(6Ј)-diphenylphosphino group(s), and an application to rhodium-catalyzed asymmetric hydrogenation. Results and DiscussionThe synthetic route of axially dissymmetric biphenyldiphosphine ligands 8a-c bearing one or two dicyclohexylphosphino group(s) and/or one or two diphenylphosphino group(s) is described in Chart 1 (8a-c were abbreviated to BIMOP, Cy-BIMOP, and MOC-BIMOP, respectively). Iodination of 2,6-dimethylnitrobenzene (1) was carried out selectively at the 3-position by heating with iodine at 90°C for 4 d in the presence of periodic acid in acetic acid containing d...

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Section: Resultsmentioning

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Preparation of Axially Chiral Biphenyl Diphosphine Ligands and Their Application in Asymmetric Hydrogenation

et al. 2004

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“…32.36). 2-(Dimethylamino)acetophenone hydrochloride is hydrogenated to the chiral amino alcohol in 96% ee with an MCCPMRh catalyst at an SCR of 100 000 [120,121]. Epinephrine hydrochloride is pro- .…”

Section: Hetero-substituted Aromatic Ketonesmentioning

confidence: 99%

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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“…The prominent natural 2-amino-arylethanols include octopamine (3a), tembemide (3b), and aegeline (3c), which display b-adrenergic receptor agonist and hypoglycemic properties. [3] Moreover, (S)-2-aminophenylethanol derivatives find utility in the synthesis of (S)-levamisole (4) analogues. [4] In pharmaceuticals, selective interactions are profoundly important because one of the enantiomers of a compound has beneficial effect, whereas the second enantiomer may have disastrous results.…”

Section: Introductionmentioning

confidence: 99%

“…[3] Moreover, (S)-2-aminophenylethanol derivatives find utility in the synthesis of (S)-levamisole (4) analogues. [4] In pharmaceuticals, selective interactions are profoundly important because one of the enantiomers of a compound has beneficial effect, whereas the second enantiomer may have disastrous results. (R)-Isoproterenol (1) possesses the desired bronchodilatory activity, whereas the (S)-isomer is approximately 90 times less potent.…”

Section: Introductionmentioning

confidence: 99%

Enantioselective Synthesis of Phenyl-ethanolamines Through Application of Chiral Sulfoxide

Sivakumar

Lahoti

Bhat

2009

Synthetic Communications

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Efficient asymmetric hydrogenation of α-aminoacetophenone derivatives leading to practical synthesis of ()-(−)-levamisole

Cited by 73 publications

References 10 publications

Preparation of Axially Chiral Biphenyl Diphosphine Ligands and Their Application in Asymmetric Hydrogenation

Preparation of Axially Chiral Biphenyl Diphosphine Ligands and Their Application in Asymmetric Hydrogenation

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

Enantioselective Synthesis of Phenyl-ethanolamines Through Application of Chiral Sulfoxide

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