ChemInform Abstract: Diastereoselective Reduction of α-Acyl-N-(bis(methylthio) methylene)alaninates and Phenylalaninates: Synthesis of α,α -Disubstituted β-Hydroxy α-Amino Esters.

ChemInform ◽  
2010 ◽  
Vol 28 (22) ◽  
pp. no-no
Author(s):  
C. ALVAREZ-IBARRA ◽  
A. G. CSAKY ◽  
M. L. QUIROGA ◽  
D. RAMIREZ
Keyword(s):  
Amino Esters ◽  
Diastereoselective Reduction

ChemInform Abstract: Chiral Cyclic β-Amino Esters. Part 2. Synthesis by Diastereoselective Reduction of Enamino Esters.

ChemInform ◽  
2010 ◽  
Vol 29 (9) ◽  
pp. no-no
Author(s):  
J. BLOT ◽  
A. BARDOU ◽  
C. BELLEC ◽  
M.-C. FARGEAU-BELLASOUED ◽  
J. P. CELERIER ◽  
...  
Keyword(s):  
Amino Esters ◽  
Diastereoselective Reduction

Diastereoselective reduction of α-acyl-N-[Bis(methylthio)methylene]alaninates and phenylalaninates: Synthesis of α,α-disubstituted β-hydroxy α-amino esters

Tetrahedron ◽  
1997 ◽  
Vol 53 (6) ◽  
pp. 2189-2198 ◽  
Author(s):  
Carlos Alvarez-Ibarra ◽  
Aurelio G Csákÿ ◽  
M Luz Quiroga ◽  
Dolores Ramírez
Keyword(s):  
Amino Esters ◽  
Diastereoselective Reduction

Chiral cyclic β-amino esters. Part II: Synthesis by diastereoselective reduction of enamino esters

1997 ◽  
Vol 38 (49) ◽  
pp. 8511-8514 ◽  
Author(s):  
J. Blot ◽  
A. Bardou ◽  
C. Bellec ◽  
M.-C. Fargeau-Bellassoued ◽  
J.P. Célérier ◽  
...  
Keyword(s):  
Amino Esters ◽  
Diastereoselective Reduction

Chemo- and Diastereoselective Reduction of .beta.-Enamino Esters: A Convenient Synthesis of Both cis- and trans-.gamma.-Amino Alcohols and .beta.-Amino Esters

1994 ◽  
Vol 59 (18) ◽  
pp. 5328-5335 ◽  
Author(s):  
Giuseppe Bartoli ◽  
Cristina Cimarelli ◽  
Enrico Marcantoni ◽  
Gianni Palmieri ◽  
Marino Petrini
Keyword(s):  
Amino Alcohols ◽  
Amino Esters ◽  
Convenient Synthesis ◽  
Diastereoselective Reduction ◽  
Cis And Trans

Exogenous Directing Group Free, Ligand-Enabled gamma-C(sp3)–H Arylation of Free Primary Aliphatic Amines and α-Amino Esters

2019 ◽  
Author(s):  
Yongzheng Ding ◽  
Shuai Fan ◽  
Xiaoxi Chen ◽  
yuzhen gao ◽  
Gang Li
Keyword(s):  
Amino Acids ◽  
Large Scale ◽  
Free Ligand ◽  
Aliphatic Amines ◽  
Rapid Synthesis ◽  
Amino Esters ◽  
Directing Group ◽  
Large Scale Synthesis ◽  
Primary Aliphatic Amines

A Pdᴵᴵ-catalyzed, ligand-enabled gamma-C(sp3)–H arylation of free primary aliphatic amines and amino esters without using an exogenous directing group is reported. This reaction is compatible with unhindered free aliphatic amines, and it is also be applicable to the rapid synthesis of biologically and synthetically valuable unnatural α-amino acids. Large scale synthesis is also feasible using this method.<br>

Diastereoselective Reduction of Selected α-substituted β-keto Esters and the Assignment of the Relative Configuration by 1H-NMR Spectroscopy

2020 ◽  
Vol 07 ◽  
Author(s):  
Christian Trapp ◽  
Corinna Schuster ◽  
Chris Drewniok ◽  
Dieter Greif ◽  
Martin Hofrichter
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Selective Reduction ◽  
Reducing Agents ◽  
Relative Configuration ◽  
Curtius Rearrangement ◽  
Keto Esters ◽  
Hydroxy Esters ◽  
Diastereoselective Reduction

Background:: Chiral β-hydroxy esters and α-substituted β-hydroxy esters represent versatile building blocks for pheromones, β-lactam antibiotics and 1,2- or 1,3-aminoalcohols. Objective:: Synthesis of versatile α-substituted β-keto esters and their diastereoselective reduction to the corresponding syn- or anti-α-substituted β-hydroxy esters. Assignment of the relative configuration by NMR-spectroscopy after a CURTIUS rearrangement of α-substituted β-keto esters to 4-substituted 5-methyloxazolidin-2-ones. Method:: Diastereoselective reduction was achieved by using different LEWIS acids (zinc, titanium and cerium) in combination with complex borohydrides as reducing agents. Assignment of the relative configuration was verified by 1H-NMR spectroscopy after CURTIUS-rearrangement of α-substituted β-hydroxy esters to 4-substituted 5-methyloxazolidin-2-ones. Results:: For the syn-selective reduction, titanium tetrachloride (TiCl4) in combination with a pyridine-borane complex (py BH3) led to diastereoselectivities up to 99% dr. High anti-selective reduction was achieved by using cerium trichloride (CeCl3) and steric hindered reducing agents such as lithium triethylborohydride (LiEt3BH). After CURTIUS-rearrangement of each α-substituted β-hydroxy ester to the corresponding 4-substituted 5-methyloxazolidin-2-one, the relative configuration was confirmed by 1H NMR-spectroscopy. Conclusion:: We have expanded the procedure of LEWIS acid-mediated diastereoselective reduction to bulky α-substituents such as the isopropyl group and the electron withdrawing phenyl ring.

ChemInform Abstract: OPTICAL SHIFT PMR SPECTROSCOPIC STUDIES ON SOME QUINOXALINE AMINO ESTERS AND DIPEPTIDES

1978 ◽  
Vol 9 (18) ◽  
Author(s):  
M. M. EL-ABADELAH ◽  
S. S. SABRI ◽  
H. D. TABBA ◽  
H. DUDDECK
Keyword(s):  
Spectroscopic Studies ◽  
Amino Esters
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