Highly Enantioselective Hydrogenation of (<i>E</i>)-β-(Acylamino)acrylates Catalyzed by Rh(I)-Complexes of Electron-Rich P-Chirogenic Diphosphines

Yasutake, Masaya; Gridnev, Ilya D.; Higashi, Natsuka; Imamoto, Tsuneo

doi:10.1021/ol0158967

Cited by 126 publications

(51 citation statements)

References 29 publications

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“…Operation of either unsaturated or dihydride pathway is possible on low-temperature hydrogenation of a catalyst-substrate complex. temperature reactions of solvate dihydride 4 produced by hydrogenation of the Rh-BisP* catalysts with methyl (Z)-␣-acetamidocinnamate and other related substrates (31)(32)(33)(34)(35)(36)(37). These experiments simulated the dihydride mechanism of the asymmetric hydrogenation and demonstrated the possibility of an almost perfect enantioselection occurring after the hydrogenactivation step.…”

Section: Formation Of the Catalyst-substrate Complex 3 And Determinatmentioning

confidence: 86%

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Asymmetric hydrogenation of α,β-unsaturated phosphonates with Rh-BisP* and Rh-MiniPHOS catalysts: Scope and mechanism of the reaction

Gridnev

Yasutake

Imamoto

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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Optically active 1,2-bis(alkylmethylphosphino)ethanes and bis(alkylmethylphosphino)methanes are unique diphosphine ligands combining the simple molecular structure and P-stereogenic asymmetric environment. This work shows that these ligands exhibit excellent enantioselectivity in rhodium-catalyzed asymmetric hydrogenation of ␣,␤-unsaturated phosphonic acid derivatives. The enantioselective hydrogenation mechanism elucidated by NMR study is also described. The ␣-hydroxy-and ␣-aminophosphonic acids have an extremely rich and varied spectrum of biological activity (1, 2) that is stipulated by their ability to act as antagonists for amino acids inhibiting enzymes involved in the amino acids' metabolism. They can be used as herbicides (3, 4), antiviral drugs (5), antibiotics (6), and neurodrugs (7). Being able to affect the biological activity of cells (8), some of them can inhibit HIV protease (9) and alanine racemase (alafosfalin) (10). Peptide ␣-hydroxyphosphonates are known to be rennin inhibitors (11).The biological activity of the phosphonic acids highly depends on the absolute configuration of its ␣-chiral center. An excellent example is alafosfalin, [N-(L-alanyl)-L-1-aminoethyl]phosphonic acid (S,R)-diastereomer. Only this diastereomer unlike (R,R)-, (S,S)-, and (R,S)-diastereomers shows high antibacterial activity (12, 13).Development of the synthesis of optically active ␣-hydroxyand ␣-aminophosphonic acids has begun only recently (2, 15). ʈ Processes applying the catalytic amounts of the source of chirality are especially attractive. Thus, hydrophosphonylation of imines catalyzed by heterobimetallic complexes Ln-K-BINOL (16) and hydrophosphonylation of aldehydes catalyzed by analogous complexes Al-Li-BINOL (17) give the ␣-amino-and ␣-hydroxyphosphonic acids, respectively, with high enantiomeric excesses (ee's). Furthermore, the catalytic asymmetric Michael addition to ␣,␤-unsaturated phosphonates (18, 19) and the allylation reaction of ␣-acetylamino-␤-ketophosphonates (20) have been successfully used for the synthesis of phosphonic acid derivatives with the stereogenic centers in the ␣-or ␤-position.Another convenient approach to the synthesis of the acids is the asymmetric hydrogenation of the corresponding unsaturated precursors. By this means, the phosphorus analogs of ␣-aminoor ␣-hydroxycarboxylic acids were obtained with up to 96% ee by using the Rh complexes of chiral phosphine ligands such as (Ϫ)-BPPM (2S,4S) (21) and DuPHOS (22). Noyori and coworkers reported that ␣-substituted ␤-ketophosphonates were subjected to enantio-and diastereoselective hydrogenation by the use of the BINAP-Ru(II) complex to give the corresponding ␤-hydroxyphosphonates with exceedingly high ee's (94-98%) (23,24). Also worth mentioning is that optically active ␣-arylsubstituted ethylphosphonates, phosphorus analogs of 2-arylpropionic acids, were produced by Ir-and Ru-catalyzed asymmetric hydrogenation of ethenylphosphonates (25,26).On the other hand, we previously designed and synthesized new bidentate phosphine ligands, (S,S...

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Section: Formation Of the Catalyst-substrate Complex 3 And Determinatmentioning

confidence: 86%

“…In addition we studied the mechanism of this hydrogenation, in conjunction with our continuing mechanistic study on rhodium-catalyzed asymmetric hydrogenations of prochiral alkenes (31)(32)(33)(34)(35)(36)(37)(38).…”

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confidence: 99%

Asymmetric hydrogenation of α,β-unsaturated phosphonates with Rh-BisP* and Rh-MiniPHOS catalysts: Scope and mechanism of the reaction

Gridnev

Yasutake

Imamoto

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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“…t-Bu-MiniPHOS as well as t-Bu-BisP* was found to show high enantioinduction ability in the hydrogenation of a-enamides, B-(acylamino)acrylates, and a,B-unsaturated phosphonates. 19,21,22 The utility of MiniPHOS was tested also in other asymmetric reactions. Asymmetric hydrogenation of itaconic acid gave almost complete enantioselectivity (Scheme 5).12,25 Rhodium-catalyzed asymmetric hydrosilylation of simple ketones afforded secondary alcohols with up to 97% ee (Scheme 6).25,27 The Michael reactions of diethylzinc with a,B-unsaturated carbonyl compounds were also promoted in good to excellent enantioselectivities (Scheme 7).…”

Section: Bis(alkylmethylphosphino)methanes (Miniphos)mentioning

confidence: 99%

P-Chiral Phosphine Ligands for Transition-Metal-Catalyzed Asymmetric Reactions

Imamoto

2007

J. Syn. Org. Chem., Jpn.

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: Optically active phosphine ligands possessing stereogenic centers on phosphorus atoms have been synthesized using phosphine-boranes as intermediates. Electron-rich P-chiral phosphine ligands (BisP*, MiniPHOS, and DiSquareP*) having a bulky alkyl group and a small alkyl group on the phosphorus atom exhibit excellent to almost perfect enantioselectivities in the Rh-catalyzed asymmetric hydrogenation of enamides and related substrates. Air-stable P-chiral phosphine ligands (t-Bu-and 1-Ad-QuinoxP*) are also prepared with the phosphine-borane methodology. These ligands have exceedingly high enantioselectivities of up to 99.9% not only in Rh-catalyzed asymmetric hydrogenation but also in Rh-or Pd-catalyzed carbon-carbon bond-forming reactions.Catalytic asymmetric synthesis is one of the most efficient methods for the production of optically active compounds. Among various asymmetric catalyses, transition-metal-catalyzed reactions have attracted a great deal of attention over the years; many catalyst systems of this class have been developed and some have been successfully applied to the industrial production of useful optically active compounds.1 Both enantioselectivity and catalytic efficiency are highly dependent on chiral ligands and central metals. Therefore, the design and synthesis of new chiral ligands is a very important research subject in this field.2Among various types of chiral ligands, phosphine ligands are the most frequently employed, owing to their inherent ability to coordinate strongly to transition metals and to promote catalytic reactions. Hence, numerous optically active phosphine ligands have been synthesized and used in tiansition metal catalyses.3 Chiral phosphine ligands reported so far are classified roughly into two types. One type is phosphines having asymmetric carbon atoms or backbone chirality. Representative examples of this type are shown in Figure 1. The stereochemical feature of this type is that the two substituents on the phosphorus atoms are diastereotopic and are capable of forming an asymmetric environment around the reaction center.The other type is the so-called P-chiral phosphine ligands, that possess stereogenic centers on the phosphorus atoms themselves. Figure 2 shows methylphenylpropylphosphine (1),4a,b CAMP (2),4c and DIPAMP (3),4d-g which are representative P-chiral phosphine ligands. These ligands played very important roles early on in the history of homogeneous asymmetric hydrogenation.4 Nevertheless, only a small number of P-chiral ligands were reported in the two decades following 1976, mainly because of the lack of efficient methods for the preparation of optically pure P-chiral phosphines, and the anticipation that some phosphines of this class are stereochemically unstable and gradually racemize via pyramidal inversion even at room temperature.5CAMP (2) DIPAMP (3) In a previous study of the synthesis and reactions of phosphine-boranes, we found that optically active P-chiral phosphine ligands could be synthesized using phosphine-boranes as intermediat...

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“…In fact, compounds 2 were a mixture of E-and Z-isomers formed in the synthesis, and they were not always easy to separate into single isomers. Generally, it is also difficult to achieve high activity and enantioselectivity for the system containing both isomers (23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33). In light of the successful development and preparation of ␣-aminomethyl acrylates 2, herein we report a highly enantioselective synthesis of ␤-amino acid derivatives by Rhcatalyzed asymmetric hydrogenation of ␣-aminomethylacrylates Asymmetric Hydrogenation of ␣-Aminomethylacrylates.…”

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confidence: 99%

“…Asymmetric hydrogenation of these substrates 2 is the simplest and most direct route to synthesize 1 because of its inherent efficiency and atom economy. In contrast to the great progress in the synthesis of ␤-substituted ␤-amino acids and derivatives via enantioselective hydrogenations (23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38), reports on the synthesis of ␣-substituted ␤-amino acids with this protocol are very limited. To the best of our knowledge, only one exceptional example has been given, very recently by Zheng and coworkers (38), using Rh-monophosphorus catalyst system for the hydrogenation of ␤-phthalimide acrylates.…”

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confidence: 99%

Enantioselective hydrogenation of α-aminomethylacrylates containing a free NH group for the synthesis of β-amino acid derivatives

Qiu

Prashad

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

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We describe highly enantioselective synthesis of ␤-amino acid derivatives (1a-c) using asymmetric hydrogenation of ␣-aminomethylacrylates (2a-c), which contain a free basic NOH group, as the key step. The ␣-aminomethylacrylates (2a-c) were prepared using the BaylisHillman reaction of an appropriate aldehyde with methyl acrylate followed by acetylation of the resulting allylic alcohols (4a-b) and S N2 -type amination of the allylic acetates (3a-b).asymmetric catalysis ͉ Baylis-Hillman reaction I n recent years, ␤-amino acids have received increasing attention as constituents of molecules with interesting biological and pharmacological activities (1-5) such as hypoglycemic and ketogenic activities. They are key moieties of a number of bioactive molecules, such as in taxol and in peptidic natural products with various enzyme inhibiting activities. Nonpeptidic ␤-amino acids are found in well known ␤-lactams. Considering their importance, asymmetric synthesis of enantiomerically pure ␤-amino acids has become an important challenge for organic chemists. The synthesis of enantiopure ␤-amino acids has been extensively studied (6-9). However, the known methods are mostly for the synthesis of ␤-substituted ␤-amino acids, and their preparation still suffers from a long synthetic sequence, low product yields, and laborious execution (10-14). For example, a recently reported synthesis of 1a involved nine steps from 3-phenylpropanoic acid (15-18). Peptide deformylase (PDF, EC 3.5.1.31), a metallopeptidase found in prokaryotic organisms, is essentially required for bacterial growth (19)(20)(21). Certain N-formyl hydroxylamine compounds were recently revealed to have good antibacterial function by means of their PDF-inhibiting capabilities. Chiral compounds 1, ␣-substituted ␤-amino acid derivatives, are key intermediates in the synthesis of this kind of compounds (15)(16)(17)(18)22). Their prochiral dehydroprecursors 2 could be prepared in high yields via a synthetic process shown in Scheme 1. Asymmetric hydrogenation of these substrates 2 is the simplest and most direct route to synthesize 1 because of its inherent efficiency and atom economy. In contrast to the great progress in the synthesis of ␤-substituted ␤-amino acids and derivatives via enantioselective hydrogenations (23-38), reports on the synthesis of ␣-substituted ␤-amino acids with this protocol are very limited. To the best of our knowledge, only one exceptional example has been given, very recently by Zheng and coworkers (38), using Rh-monophosphorus catalyst system for the hydrogenation of ␤-phthalimide acrylates. However, the activity of the catalyst was not high, and only E-isomers of substituted ␤-phthalimide acrylates were investigated. In fact, compounds 2 were a mixture of E-and Z-isomers formed in the synthesis, and they were not always easy to separate into single isomers. Generally, it is also difficult to achieve high activity and enantioselectivity for the system containing both isomers (23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33). In light of the suc...

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Highly Enantioselective Hydrogenation of (E)-β-(Acylamino)acrylates Catalyzed by Rh(I)-Complexes of Electron-Rich P-Chirogenic Diphosphines

Cited by 126 publications

References 29 publications

Asymmetric hydrogenation of α,β-unsaturated phosphonates with Rh-BisP* and Rh-MiniPHOS catalysts: Scope and mechanism of the reaction

Asymmetric hydrogenation of α,β-unsaturated phosphonates with Rh-BisP* and Rh-MiniPHOS catalysts: Scope and mechanism of the reaction

P-Chiral Phosphine Ligands for Transition-Metal-Catalyzed Asymmetric Reactions

Enantioselective hydrogenation of α-aminomethylacrylates containing a free NH group for the synthesis of β-amino acid derivatives

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