An Efficient Method for Constructing Cyclic β-Amino Acids Bearing Quaternary Stereocenters

Synlett ◽  
2019 ◽  
Vol 30 (05) ◽  
pp. 593-599 ◽  
Author(s):  
Shende Jiang ◽  
Guang Yang ◽  
Shuanglin Qin ◽  
Tongtong Liu ◽  
Yunhao Luo ◽  
...  
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Efficient Method ◽  
Ester Group ◽  
Chiral Auxiliary ◽  
Allyl Ester ◽  
Stereogenic Centers ◽  
Quaternary Stereocenters ◽  
High Yields ◽  
Quaternary Stereogenic Centers

This paper describes an efficient method for constructing cyclic β-amino acids bearing quaternary stereocenters. NaHMDS-promoted asymmetric α-alkylation was employed to obtain the key intermediates with quaternary stereogenic centers, which were subsequently reduced by NaBH4 in 10% methanol in THF, with high yields and high diastereoselectivities. By removing the allyl ester group and the chiral auxiliary, the corresponding cyclic β-amino acid hydrochlorides were finally obtained.

Highly enantioselective synthesis of bisoxindoles with two vicinal quaternary stereocenters via Lewis base mediated addition of oxindoles to isatin-derived ketimines

2014 ◽  
Vol 12 (32) ◽  
pp. 6085-6088 ◽  
Author(s):  
Zhongkai Tang ◽  
Yan Shi ◽  
Haibin Mao ◽  
Xuebin Zhu ◽  
Weipeng Li ◽  
...  
Keyword(s):  
Efficient Method ◽  
Enantioselective Synthesis ◽  
Lewis Base ◽  
Highly Efficient ◽  
Stereogenic Centers ◽  
Quaternary Stereocenters ◽  
Quaternary Stereogenic Centers

A highly efficient method provides access to the bisoxindole structure moiety with two vicinal quaternary stereogenic centers (>99 : 1 dr, >99% ee).

A facile one pot route for the synthesis of imide tethered peptidomimetics

2016 ◽  
Vol 14 (2) ◽  
pp. 556-563 ◽  
Author(s):  
Veladi Panduranga ◽  
Girish Prabhu ◽  
Roopesh Kumar ◽  
Basavaprabhu Basavaprabhu ◽  
Vommina V. Sureshbabu
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Efficient Method ◽  
One Pot ◽  
Protected Amino Acid

A simple and efficient method for the synthesis of N,N’-orthogonally protected imide tethered peptidomimetics is presented. The imide peptidomimetics were synthesized by coupling the in situ generated selenocarboxylate of Nα-protected amino acids with Nα-protected amino acid azides in good yields.

UV-Light-Induced Dehydrogenative N-Acylation of Amines with 2-Nitrobenzaldehydes to Give 2-Aminobenzamides

Synthesis ◽  
2022 ◽  
Author(s):  
Dishu Zeng ◽  
Tianbao Yang ◽  
Niu Tang ◽  
Wei Deng ◽  
Jiannan Xiang ◽  
...  
Keyword(s):  
Amino Acid ◽  
Organic Synthesis ◽  
Efficient Method ◽  
Building Block ◽  
Room Temperature ◽  
Uv Light ◽  
Amino Acid Derivatives ◽  
One Pot ◽  
Plausible Mechanism ◽  
High Yields

A simple, mild, green and efficient method for the synthesis of 2-aminobenzamides was highly desired in organic synthesis. Herein, we developed an efficient, one-pot strategy for the synthesis of 2-aminobenzamides with high yields irradiated by UV light. 32 examples proceeded successfully by this photo-induced protocol. The yield reached up to 92%. The gram scale was also achieved easily. This building block could be applied in the preparation of quinazolinones derivatives. Amino acid derivatives could be employed smoothly at room temperature. Finally, a plausible mechanism was proposed.

scholarly journals NHC-Catalyzed Organocatalytic Asymmetric Approach to 2,2-Disubstituted Benzofuran-3(2H)-ones Containing Fully Substituted Quaternary Stereogenic Center

Catalysts ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 192 ◽  
Author(s):  
Zbigniew Rafiński
Keyword(s):  
Stetter Reaction ◽  
Highly Efficient ◽  
Stereogenic Centers ◽  
Michael Acceptors ◽  
High Yields ◽  
Stereogenic Center ◽  
Quaternary Stereogenic Centers ◽  
Triazolium Salts

A highly efficient and enantioselective approach to the synthesis of functionalized benzofuran-3(2H)-ones is presented. It proceeds via an intramolecular Stetter reaction using β,β-disubstituted Michael acceptors in the construction of five-membered rings with fully-substituted quaternary stereogenic centers and is promoted by terpene-derived triazolium salts. As a result, a series of chiral 2,2-disubstituted benzofuran-3(2H)-one derivatives with linear, branched, and cyclic aliphatic substitutions on the quaternary stereogenic center were obtained in high yields and with excellent enantioselectivities of up to 99% ee.

Some N-acyl-D-amino acid derivatives having antibotulinal properties

1987 ◽  
Vol 33 (7) ◽  
pp. 577-582 ◽  
Author(s):  
A. Paquet ◽  
K. Rayman
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Aspartic Acid ◽  
Sodium Nitrite ◽  
Amino Acid Derivatives ◽  
Ester Method ◽  
Succinimidyl Ester ◽  
High Yields ◽  
Derivatives Of ◽  
Acyl Derivatives

Several N-acyl derivatives of D-tryptophan, D-alanine, D-methionine, D-valine, and D-aspartic acid were synthesized in high yields using the succinimidyl ester method and examined for their antibotulinal properties. In conjunction with 60 ppm of sodium nitrite, sorbyl-D-tryptophan, sorbyl-D-alanine, myristoyl-D-aspartic acid, and glycyl-D-alanine were highly inhibitory. In the absence of sodium nitrite, the N-acyl derivatives of the D-amino acids were not inhibitory. On its own, 60 ppm of sodium nitrite was only slightly inhibitory. Sorbyl-L-tryptophan and sorbyl-L-alanine had no effect in the presence or absence of 60 ppm of sodium nitrite.

P-Methoxybenzyl esters of amino acids-their preparation and use in peptide synthesis

1971 ◽  
Vol 24 (8) ◽  
pp. 1695 ◽  
Author(s):  
BJ Maclaren
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Peptide Synthesis ◽  
Trifluoroacetic Acid ◽  
Ester Group

Various N-protected amino acids have been alkylated with p- methoxybenzyl chloride to give the corresponding esters. These were then converted into amino acid p-methoxybenzyl esters by selective acidolysis of the N-o-nitrophenylsulphenyl and N-trityl derivatives, or in poor yield by hydrazinolysis of the N-phthaloyl derivative. S- Benzylcysteine p-methoxybenzyl ester is obtained without racemiza- tion. These esters have been applied to the syntheses of several dipeptides, the ester group being cleaved by cold trifluoroacetic acid.

scholarly journals Stereospecific Hydroformylation of 1-Substituted Cyclopent-3-en-1-ols: A Concise Access to Bridged [2, 2, 1] Bicyclic Lactones With A Quaternary Stereocenter

2021 ◽  
Author(s):  
Shuailong Li ◽  
Zhuangxing Li ◽  
Mingzheng Li ◽  
Lin He ◽  
Xumu Zhang ◽  
...  
Keyword(s):  
Efficient Method ◽  
Enantiomeric Excess ◽  
Ester Group ◽  
Hydroxyl Group ◽  
Chiral Ligand ◽  
One Pot ◽  
Quaternary Stereocenter ◽  
High Yields ◽  
Bicyclic Lactones

Abstract An efficient method for enantioselective construction of bridged [2, 2, 1] bicyclic lactones bearing a quaternary stereocenter was achieved by Rh-catalyzed asymmetric hydroformylation /intramolecular cyclization/PCC oxidation. By employing a hybrid phosphine-phosphite chiral ligand, a series of cyclopent-3-en-1-ols were transformed into their corresponding y-hydroxyl aldehydes with specific syn-selectivity, then hemiacetal formed in situ and oxidized by PCC in one-pot, affording bridged [2,2,1] bicyclic lactones in high yields and excellent enantiomeric excess. Replacing the hydroxyl group by an ester group, cyclopentanecarbaldehydes with a chiral all-carbon quaternary stereocenter in the γ-position can be generated efficiently. Gram-scale reaction and several transformations to corresponding amide, alcohol and acid demonstrated the practical value of this methodology.

scholarly journals Rhodium-catalyzed asymmetric addition of arylboronic acids to cyclic N-sulfonyl ketimines towards the synthesis of α,α-diaryl-α-amino acid derivatives

2015 ◽  
Vol 13 (17) ◽  
pp. 4918-4924 ◽  
Author(s):  
Ryosuke Takechi ◽  
Takahiro Nishimura
Keyword(s):  
Amino Acid ◽  
Ester Group ◽  
Amino Acid Derivatives ◽  
Asymmetric Addition ◽  
Arylboronic Acids ◽  
High Yields ◽  
Diene Complex

Rhodium/chiral diene complex-catalyzed asymmetric addition of arylboronic acids to cyclic ketimines having an ester group proceeded to give the corresponding α-amino acid derivatives in high yields with high enantioselectivity.

Phase-transfer catalyzed enantioselective α-alkylation of α-acyloxymalonates: construction of chiral α-hydroxy quaternary stereogenic centers

RSC Advances ◽  
2016 ◽  
Vol 6 (81) ◽  
pp. 77427-77430 ◽  
Author(s):  
Min Woo Ha ◽  
Sujee Choi ◽  
Seek Kim ◽  
Jun Young Lee ◽  
Jae Kyun Lee ◽  
...  
Keyword(s):  
Natural Products ◽  
Efficient Method ◽  
Phase Transfer ◽  
Enantioselective Synthesis ◽  
Tertiary Alcohols ◽  
Stereogenic Centers ◽  
Quaternary Stereogenic Centers

The enantioselective synthesis of α-acyloxy-α-alkylmalonates was developed as an efficient method for producing chiral α-tertiary alcohols, which are potentially valuable intermediates in the synthesis of natural products and pharmaceuticals.

scholarly journals Synthesis and Evaluation of Novel Iminosugars Prepared from Natural Amino Acids

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 394
Author(s):  
Alejandro Puet ◽  
Gema Domínguez ◽  
Francisco Javier Cañada ◽  
Javier Pérez-Castells
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Molecular Recognition ◽  
Inhibitory Activity ◽  
Inhibition Activity ◽  
Ring Closing Metathesis ◽  
Stereogenic Centers ◽  
Activity Enhancement ◽  
Natural Amino Acids

Cyclopropanated iminosugars have a locked conformation that may enhance the inhibitory activity and selectivity against different glycosidases. We show the synthesis of new cyclopropane-containing piperidines bearing five stereogenic centers from natural amino acids l-serine and l-alanine. Those prepared from the latter amino acid may mimic l-fucose, a natural-occurring monosaccharide involved in many molecular recognition events. Final compounds prepared from l-serine bear S configurations on the C5 position. The synthesis involved a stereoselective cyclopropanation reaction of an α,β-unsaturated piperidone, which was prepared through a ring-closing metathesis. The final compounds were tested as possible inhibitors of different glycosidases. The results, although, in general, with low inhibition activity, showed selectivity, depending on the compound and enzyme, and in some cases, an unexpected activity enhancement was observed.

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