133775-02-7Relevant academic research and scientific papers
A new method for production of chiral 2-aryloxypropanoic acids using effective kinetic resolution of racemic 2-aryloxycarboxylic acids
Tengeiji, Atsushi,Nakata, Kenya,Ono, Keisuke,Shiina, Isamu
, p. 1227 - 1252 (2013/08/23)
We report a novel method for the preparation of 2-aryloxypropanoic acids by kinetic resolution of racemic 2-aryloxypropanoic acids using enantioselective esterification. The usage of pivalic anhydride (Piv2O) as an activating agent, bis(a-naphthyl)methanol ((α-Np)2CHOH) as an achiral alcohol, and (+)-benzotetramisole ((+)-BTM) as a chiral acyl-transfer catalyst enables the effective separation of various racemic 2-aryloxypropanoic acids to afford optically active carboxylic acids and the corresponding esters with high enantioselectivities. Furthermore, theoretical calculations of the transition states required to form the chiral esters successfully proved the enantiomer recognition mechanism of the asymmetric esterification.
Molecular Sieve Controlled Diastereoselectivity: Effect in the Palladium-Catalyzed Cyclization of cis-1,2-Divinylcyclohexane with α-Oxygen-Substituted Acids as Chiral Nucleophiles
Tottie, Louise,Baeckstroem, Peter,Moberg, Christina,Tegenfeldt, Joergen,Heumann, Andreas
, p. 6579 - 6587 (2007/10/02)
Molecular sieves have been shown to improve greatly the stereoselectivity in the palladium(II)-catalyzed reaction of cis-1,2-divinylcyclohexane with chiral acids.Reactions run with molecular sieves and derivatives of (R)-lactic acids as nucleophiles always yielded products with S configuration at the newly formed chiral center in contrast to reactions without molecular sieves that gave products with either S or R configuration at this chiral center.It appears that this effect has not been observed previously.Only water-containing molecular sieves increased the stereoselectivity.A chiral palladium complex was formed faster in the presence of molecular sieves, but use of this complex as catalyst in the cyclization did not result in increased selectivity.The best stereoselectivity was found for molecular sieves with a high sodium content (Lancaster 13X and 4-Angstroem sieves).
