18672-09-8Relevant academic research and scientific papers
Planar chiral [2.2]paracyclophane-based bisoxazoline ligands: Design, synthesis, and use in cu-catalyzed inter- and intramolecular asymmetric O-H insertion reactions
Kitagaki, Shinji,Murata, Shunsuke,Asaoka, Kisaki,Sugisaka, Kenta,Mukai, Chisato,Takenaga, Naoko,Yoshida, Keisuke
, p. 1006 - 1014 (2018/10/08)
Centrally chiral bisoxazolines connected directly to a planar chiral [2.2]paracyclophane backbone were synthesized and evaluated as asymmetric ligands in Cu-catalyzed intermolecular ethanolic O-H insertion reactions of α-diazo esters. The reactivities and enantioselectivities of Cu complexes of the synthesized bisoxazoline ligands were lower than those of ligands without central chirality. However, planar chiral [2.2] paracyclophane-based bisoxazoline ligands with an inserted benzene spacer that had a sterically demanding isopropyl substituent showed good enantioselectivities in inter- and intramolecular aromatic O-H insertion reactions, without the aid of central chirality.
Rapid and efficient synthesis of (R)-aryloxypropionic acid esters under microwave irradiation
Ochal, Zbigniew,Durka, Krzysztof,Banach, Lukasz
experimental part, p. 3209 - 3213 (2010/12/24)
A series of (R)-(+)-ethyl aryloxypropionates (4a-4p) have been synthesized by the reaction of substituted phenols with ethyl (S)-(-)-tosyloxy lactate under the conditions of microwave irradiation and without solvents. The reaction conditions have been optimized. A good method for the preparation of (R)-(+)-ethyl aryloxypropionate was developed, with good yields, high enantiomer excess, short reaction times, easy workup, and simple procedure. Copyright Taylor & Francis Group, LLC.
Synthesis of 2-aryloxypropanoic acids analogues of clofibric acid and assignment of the absolute configuration by 1H NMR spectroscopy and DFT calculations
Ammazzalorso, Alessandra,Bettoni, Giancarlo,De Filippis, Barbara,Fantacuzzi, Marialuigia,Giampietro, Letizia,Giancristofaro, Antonella,Maccallini, Cristina,Re, Nazzareno,Amoroso, Rosa,Coletti, Cecilia
, p. 989 - 997 (2008/09/21)
A new set of optically active 2-aryloxypropanoic acids has been synthesized through a simple strategy, in good yields and excellent enantiomeric excesses. Their absolute configuration was assigned by means of a NMR-based approach consisting of the derivatization of the carboxylic acids with ethyl mandelate and the comparison of the chemical shifts of the obtained diastereomers. The effectiveness of such an approach has been tested against a larger set of chiral α-substituted-carboxylic acids and by performing high level density functional theory (DFT) calculations on a set of low energy conformations for each diastereomeric derivative. The employed computational procedure has enabled us to find a semiquantitative relationship between the experimental NMR data and the theoretically calculated energy gaps which confirms the theoretical foundations of the NMR strategy and allows to understand when and why it is most likely to fail.
Highly enantioselective insertion of carbenoids into O-H bonds of phenols: An efficient approach to chiral α-aryloxycarboxylic esters
Chen, Chao,Zhu, Shou-Fei,Liu, Bin,Wang, Li-Xin,Zhou, Qi-Lin
, p. 12616 - 12617 (2008/03/14)
A highly efficient copper-catalyzed asymmetric carbenoid insertion into O-H bonds of phenols has been realized by using chiral spiro bisoxazoline ligands, affording α-aryloxypropionates and the related propionic acids in high yields with excellent enantiomeric excesses. Copyright
PROCESS FOR PREPARING (R)-ARYLOXYPROPIONIC ACID ESTER DERIVATIVES
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Page 7, (2008/06/13)
The present invention relates to a method for preparing optically active (R)-aryloxypropionic acid ester derivatives, and more particularly to a method for preparing (R)- aryloxypropionic acid ester derivatives with high optical purity and good yield at low cost from phenol derivatives with various substituted functional groups and (S)-alkyl O-arylsulfonyl lactates.
