A catalytic enantioselective synthesis of α-methyl amino acid derivatives by phase-transfer catalysis

O’Donnell, Martin J.; Wang, Shengde

doi:10.1016/s0957-4166(00)82288-0

Cited by 138 publications

(55 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Acid 10 was linked to l-tyrosine methyl ester to give dipeptide 11, which was treated with copper(II) acetate and 4-dimethylaminopyridine in the presence of 4 molecular sieves to afford the desired cycloisodityrosine (12) in 47 % yield. N-Methylation of compound 12 under phase-transfer catalysis conditions [22] gave the fully functionalized cycloisodityrosine (13), which was usable for the synthesis of compound 4. The Boc group in compound 13 was removed, and the resulting amine was coupled with tetrapeptide 14 provided hexapeptide 15.…”

Section: Wwwchemeurjorgmentioning

confidence: 99%

Isolation, Structure Determination, and Synthesis of Allo‐RA‐V and Neo‐RA‐V, RA‐Series Bicyclic Peptides from Rubia cordifolia L.

Hitotsuyanagi

Odagiri

Kato

et al. 2012

Chemistry A European J

View full text Add to dashboard Cite

Two bicyclic hexapeptides, allo-RA-V (4) and neo-RA-V (5), and one cyclic hexapeptide, O-seco-RA-V (6), were isolated from the roots of Rubia cordifolia L. Their gross structures were elucidated on the basis of spectroscopic analysis and X-ray crystallography of compound 5. The absolute stereochemistry of compounds 4 and 5 were established by their total syntheses, and the absolute stereochemistry of compound 6 by chemical correlation with deoxybouvardin (3). Comparison of the 3D structures of highly active RA-VII (1) with less-active compounds 4 and 5 suggests that the orientation of the Tyr-5 and/or Tyr-6 phenyl rings plays a significant role in their biological activity. The isolation of peptides 4-6, along with compound 3, and the comparison of their structures seem to indicate that peptide 6 may be the common precursor to bicyclic peptides 3-5 in the plant.

show abstract

Section: Wwwchemeurjorgmentioning

confidence: 99%

Isolation, Structure Determination, and Synthesis of Allo‐RA‐V and Neo‐RA‐V, RA‐Series Bicyclic Peptides from Rubia cordifolia L.

Hitotsuyanagi

Odagiri

Kato

et al. 2012

Chemistry A European J

View full text Add to dashboard Cite

show abstract

“…The pioneering studies of O'Donnell and co-workers in 1989 led to the development of a highly practical enantioselective alkylation of a prochiral-protected glycine derivative using Cinchona alkaloid ammonium salts to produce chiral a-amino acids. [195][196][197][198][199][200] Later, Corey [201][202][203] and Lygo [204][205][206][207] independently greatly improved this catalyst system. [208][209][210] Although many types of chiral phase-transfer catalysts have been developed, Cinchona alkaloid derivatives give more impressive enantioselectivity for a range of reactions than do other catalysts, with few exceptions, [213][214][215][216][217][218][219][220][221][222] such as N-spiro binaphtyl derivatives.…”

Section: Catalytic Asymmetric Epoxidation 3-1 Catalytic Asymmetric Ementioning

confidence: 99%

Enantioselective Total Syntheses of Several Bioactive Natural Products Based on the Development of Practical Asymmetric Catalysis

Ohshima

2004

CHEMICAL & PHARMACEUTICAL BULLETIN

View full text Add to dashboard Cite

I present herewith enantioselective total syntheses of several bioactive natural products, such as (؊)-strychnine, (؉)-decursin, (؊)-cryptocaryolone diacetate, (؊)-fluoxetine, and aeruginosin 298-A, based on practical asymmetric catalyses (Michael reaction, epoxidation, and phase-transfer reaction) that I developed with coworkers in Prof. Shibasaki's group over the past 5 years. In the first part of this review, I discuss the great improvement of catalyst efficiency in an ALB-catalyzed asymmetric Michael reaction of malonate and application to the pre-manufacturing scale (greater than kilogram scale) and enantioselective total synthesis of (؊)-strychnine with the development of novel domino cyclization. To broaden the substrate generality of the Michael reaction, we developed a highly stable, storable, and reusable La-O-linked-BINOL complex. Further extension of the reaction using b b-keto ester as a Michael donor was achieved with the development of a La-NR-linked-BINOL complex, thereby improving indole alkaloid syntheses. In the second section, I discuss enantioselective total synthesis of (؉)-decursin using catalytic asymmetric epoxidation. To achieve the synthesis, we developed a new La-BINOL-Ph 3 As‫؍‬O (1 : 1 : 1) complex catalyst system, which has much higher reactivity and broader substrate generality than the previously developed catalyst systems. This allowed us to achieve catalytic asymmetric epoxidation of a a,b b-unsaturated carboxylic acid derivatives with high enantioselectivity and broad substrate generality for the first time by changing the lanthanide metal and reaction conditions. Among them, catalytic asymmetric epoxidation of a a,b b-unsaturated morpholinyl amides is quite useful in terms of synthetic utility of the corresponding a a,b b-epoxy morpholinyl amides. Highly catalyst-controlled enantio-or diastereoselective epoxidation of the a a,b b-unsaturated morpholinyl amides, coupled with diastereoselective reduction of b b-hydroxy ketones, enabled the synthesis of all possible stereoisomers of 1,3-polyol arrays with successful enantioselective total synthesis of several 1,3-polyol natural products, such as (؊)-cryptocaryolone diacetate. In addition, the development of a new regioselective epoxide-opening reaction of a a,b b-epoxy amides to the corresponding a a-and b b-hydroxy amides enhanced the usefulness of the present epoxidation and was applied to the enantioselective total synthesis of (؊)-fluoxetine. In the final section, I report the development of a new asymmetric two-center organocatalyst (TaDiAS) and its application to the enantioselective synthesis of aeruginosin 298-A and its analogues. Because of the remarkable structural diversity of TaDiAS, a practical asymmetric phase-transfer reaction with broad substrate generality was achieved. As a result, we succeeded in developing a highly versatile synthetic method for aeruginosin 298-A and its analogues. Inhibitory activity studies of the compounds against the serine protease trypsin provided preliminary information about their str...

show abstract

“…This change in the nature of the imine group from glycine to alanine is important, as the benzophenone imine, used for the monoalkylation of glycine derivatives 5, does not allow a second alkylation process because of the decreased acidity of the α-methine proton in the monoalkylated derivative. [13] The enantioselective synthesis of α,α-dialkylamino acids by subsequent α-alkylation of derivatives of type 6 is con-sidered to be a more difficult process in comparison to the α-monoalkylation of glycine derivatives 5; generally, lower enantioselectivities are observed. Thus, the only example in which a chiral ammonium salt was prepared directly from a natural, simple, and cheap chiral source was reported by O'Donnell who employed N-benzyl cinchoninium chloride 3 as a phase-transfer organocatalyst for the enantioselective α-alkylation of 4-chlorobenzaldehyde-derived iminic alaninate 6 (Ar = 4-ClC 6 H 4 , R 1 = Me, R 2 = tBu); however, low ee values were obtained such as the 40 % ee for the α-benzylation reaction.…”

Section: Introductionmentioning

confidence: 99%

Convenient Conditions for the Enantioselective Synthesis of α‐Methyl‐α‐amino Acids with the Use of Cinchona Ammonium Salts as Phase‐Transfer Organocatalysts

2007

View full text Add to dashboard Cite

Keywords:Enantioselective synthesis / Phase-transfer catalysis / Amino acids / Ammonium salts / OrganocatalysisThe enantioselective α-alkylation of 2-naphthalenecarbaldehyde aldimine alanine tert-butyl ester is carried out by using N-anthracenylmethyl ammonium salts from the simple and unmodified cinchonidine and cinchonine alkaloids as phase-transfer organocatalysts, which affords (S)-and (R)-enantioenriched α-methyl-α-amino acid (AMAA) derivatives in 71-98 % yield and 79-96 % ee. The employed reaction con-

show abstract

A catalytic enantioselective synthesis of α-methyl amino acid derivatives by phase-transfer catalysis

Cited by 138 publications

References 37 publications

Isolation, Structure Determination, and Synthesis of Allo‐RA‐V and Neo‐RA‐V, RA‐Series Bicyclic Peptides from Rubia cordifolia L.

Isolation, Structure Determination, and Synthesis of Allo‐RA‐V and Neo‐RA‐V, RA‐Series Bicyclic Peptides from Rubia cordifolia L.

Enantioselective Total Syntheses of Several Bioactive Natural Products Based on the Development of Practical Asymmetric Catalysis

Convenient Conditions for the Enantioselective Synthesis of α‐Methyl‐α‐amino Acids with the Use of Cinchona Ammonium Salts as Phase‐Transfer Organocatalysts

Contact Info

Product

Resources

About