Exceptional Chiral Recognition of Racemic Carboxylic Acids by Calix[4]arenes Bearing Optically Pure α,β-Amino Alcohol Groups

2004 ◽  
Vol 6 (8) ◽  
pp. 1189-1192 ◽  
Author(s):  
Yan-Song Zheng ◽  
Chun Zhang
Keyword(s):  
Carboxylic Acids ◽  
Amino Alcohol ◽  
Chiral Recognition ◽  
Optically Pure

Amino alcohol-derived chiral ionic liquids: structural investigations toward chiral recognition

2015 ◽  
Vol 26 (18-19) ◽  
pp. 1069-1082 ◽  
Author(s):  
Maria Vasiloiu ◽  
Isabella Cervenka ◽  
Peter Gaertner ◽  
Matthias Weil ◽  
Christian Schröder ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Amino Alcohol ◽  
Chiral Recognition ◽  
Structural Investigations ◽  
Chiral Ionic Liquids

scholarly journals Optically Pure Aziridin-2-yl Methanols as Readily Available 1H NMR Sensors for Enantiodiscrimination of α-Racemic Carboxylic Acids Containing Tertiary or Quaternary Stereogenic Centers

2020 ◽  
Vol 85 (18) ◽  
pp. 11794-11801
Author(s):  
Martyna Malinowska ◽  
Szymon Jarzyński ◽  
Adam Pieczonka ◽  
Michał Rachwalski ◽  
Stanisław Leśniak ◽  
...  
Keyword(s):  
Carboxylic Acids ◽  
1H Nmr ◽  
Stereogenic Centers ◽  
Optically Pure ◽  
Quaternary Stereogenic Centers

Synthesis of novel chiral fluorescent sensors and their application in enantioselective discrimination of chiral carboxylic acids

2019 ◽  
Vol 43 (9-10) ◽  
pp. 340-346 ◽  
Author(s):  
Qiuhan Yu ◽  
Weiwen Lu ◽  
Zhiqiang Ding ◽  
Min Wei ◽  
Zhenya Dai
Keyword(s):  
Carboxylic Acids ◽  
Chiral Recognition ◽  
Amino Alcohols ◽  
Fluorescent Sensors ◽  
Enantiomerically Pure ◽  
Wide Range

Novel chiral fluorescent sensors are synthesized from a dibromide containing a tetraphenylethylene moiety and enantiomerically pure amino alcohols and an amine. The sensors are applied for the chiral recognition of a wide range of chiral carboxylic acids and related derivatives.

New Synthesis of Optically Pure α-Branched Aliphatic Carboxylic Acids from Amidines

Synthesis ◽  
2004 ◽  
pp. 1041-1046 ◽  
Author(s):  
Emanuela Erba ◽  
Flavio Cassani ◽  
Giuseppe Celentano ◽  
Donato Pocar
Keyword(s):  
Carboxylic Acids ◽  
New Synthesis ◽  
Aliphatic Carboxylic Acids ◽  
Optically Pure

Hydrogen bonding in enantiomeric versus racemic mono-carboxylic acids; a case study of 2-phenoxypropionic acid

2003 ◽  
Vol 59 (1) ◽  
pp. 132-140 ◽  
Author(s):  
Henning Osholm Sørensen ◽  
Sine Larsen
Keyword(s):  
Hydrogen Bond ◽  
Hydrogen Bonding ◽  
Crystal Structures ◽  
Carboxylic Acids ◽  
Crystal Packing ◽  
Cyclic Dimer ◽  
Optically Pure ◽  
Pure Enantiomer ◽  
Hydrogen Bonded

The structural and thermodynamic backgrounds for the crystallization behaviour of racemates have been investigated using 2-phenoxypropionic acid (PPA) as an example. The racemate of PPA behaves normally and forms a racemic compound that has a higher melting point and is denser than the enantiomer. Low-temperature crystal structures of the pure enantiomer, the enantiomer cocrystallized with n-alkanes and the racemic acid showed that hydrogen-bonded dimers that form over crystallographic symmetry elements exist in all but the structure of the pure enantiomer. A database search for optically pure chiral mono-carboxylic acids revealed that the hydrogen-bonded cyclic dimer is the most prevalent hydrogen-bond motif in chiral mono-carboxylic acids. The conformation of PPA depends on the hydrogen-bond motif; the antiplanar conformation relative to the ether group is associated with a catemer hydrogen-bonding motif, whereas the more abundant synplanar conformation is found in crystals that contain cyclic dimers. Other intermolecular interactions that involve the substituent of the carboxylic group were identified in the crystals that contain the cyclic dimer. This result shows how important the nature of the substituent is for the crystal packing. The differences in crystal packing have been related to differences in melting enthalpy and entropy between the racemic and enantiomeric acids. In a comparison with the equivalent 2-(4-chlorophenoxy)-propionic acids, the differences between the crystal structures of the chloro and the unsubstituted acid have been identified and related to thermodynamic data.

Chiral Recognition Studies of α-(Nonafluoro-tert-butoxy)carboxylic Acids by NMR Spectroscopy

2015 ◽  
Vol 80 (12) ◽  
pp. 6267-6274 ◽  
Author(s):  
Anikó Nemes ◽  
Tamás Csóka ◽  
Szabolcs Béni ◽  
Viktor Farkas ◽  
József Rábai ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Carboxylic Acids ◽  
Chiral Recognition

scholarly journals Efficient Enantiodifferentiation of Carboxylic Acids Using BINOL-Based Amino Alcohol as a Chiral NMR Solvating Agent

2020 ◽  
Vol 8 ◽  
Author(s):  
Gaowei Li ◽  
Minshan Ma ◽  
Guifang Wang ◽  
Xiaojuan Wang ◽  
Xinxiang Lei
Keyword(s):  
Carboxylic Acids ◽  
Amino Alcohol

scholarly journals (±)-trans-1,2-Cyclohexanediamine-Based Bis(NHC) Ligand for Cu-Catalyzed Asymmetric Conjugate Addition Reaction

Catalysts ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 780 ◽  
Author(s):  
Azusa Ishibashi ◽  
Shun Kamihigashi ◽  
Yuuki Iwai ◽  
Satoshi Sakaguchi
Keyword(s):  
Catalytic System ◽  
Amino Alcohol ◽  
Addition Reaction ◽  
Conjugate Addition ◽  
Addition Reactions ◽  
Chiral Ligand ◽  
Facial Selectivity ◽  
Ligand Precursors ◽  
Optically Pure

Bis(NHC) ligand precursors, L1, based on trans-1,2-diaminocyclohexane were designed and synthesized. To introduce chirality at the hydroxyamide side arm on the NHC of L1, a chiral β-amino alcohol, such as enantiopure leucinol, was used. Cu-catalyzed asymmetric conjugate addition reactions of cyclic and acyclic enones with Et2Zn were selected to evaluate the performance of L1 as a chiral ligand. For the reaction of cyclic enone, a combination of [bis(trimethylsilyl)acetylene]-(hexafluoroacetylacetonato)copper(I) (Cu(hfacac)(btmsa)) with a (±)-trans-1,2-cyclohexanediamine-based bis(NHC) ligand precursor, (rac; S,S)-L1, which was prepared from (S)-leucinol, was the most effective. Thus, treating 2-cyclohexen-1-one (3) with Et2Zn in the presence of catalytic amounts of Cu(hfacac)(btmsa) and (rac; S,S)-L1 afforded (R)-3-ethylcyclohexanone ((R)-4) with 97% ee. Similarly, use of (rac; R,R)-L1, which was prepared from (R)-leucinol, produced (S)-4 with 97% ee. Conversely, for the asymmetric 1,4-addition reaction of the acyclic enone, optically pure (−)-trans-1,2-cyclohexanediamine-based bis(NHC) ligand precursor, (R,R; S,S)-L1, worked efficiently. For example, 3-nonen-2-one (5) was reacted with Et2Zn using the CuOAc/(R,R; S,S)-L1 catalytic system to afford (R)-4-ethylnonan-2-one ((R)-6) with 90% ee. Furthermore, initially changing the counterion of the Cu precatalyst between an OAc and a ClO4 ligand on the metal reversed the facial selectivity of the approach of the substrates. Thus, the conjugate addition reaction of 5 with Et2Zn using the Cu(ClO4)2/(R,R; S,S)-L1 catalytic system, afforded (S)-6 with 75% ee.

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