5469-44-3Relevant academic research and scientific papers
The Enantioselective Dakin-West Reaction
Wende, Raffael C.,Seitz, Alexander,Niedek, Dominik,Schuler, S?ren M. M.,Hofmann, Christine,Becker, Jonathan,Schreiner, Peter R.
supporting information, p. 2719 - 2723 (2016/02/27)
Here we report the development of the first enantioselective Dakin-West reaction, yielding α-acetamido methylketones with up to 58 % ee with good yields. Two of the obtained products were recrystallized once to achieve up to 84 % ee. The employed methylimidazole-containing oligopeptides catalyze both the acetylation of the azlactone intermediate and the terminal enantioselective decarboxylative protonation. We propose a dispersion-controlled reaction path that determines the asymmetric reprotonation of the intermediate enolate after the decarboxylation.
Regioselective synthesis of tetrasubstituted pyrroles by 1,3-dipolar cycloaddition and spontaneous decarboxylation
Kim, Yongju,Kim, Jonghoon,Park, Seung Bum
supporting information; experimental part, p. 17 - 20 (2009/08/07)
We developed a novel regioselective synthesis of tetrasubstituted pyrroles via the classic 1,3-dipolar cycloaddition of α,β-unsaturated benzofuran-3(2H)-one and azlactones (1) followed by spontaneous decarboxylation. The complete regiochemical control of tetrasubstituted pyrroles was confirmed by the orthogonal synthesis of complementary regioisomers (7a and 7b) simply by using different azlactones (1a and 1b, respectively).
Diastereochemical diversity of imidazoline scaffolds via substrate controlled TMSCI mediated cycloaddition of azlactones
Sharma, Vasudha,Tepe, Jetze J.
, p. 5091 - 5094 (2007/10/03)
(Chemical Equation Presented) We report herein a trimethylsilyl chloride mediated substrate controlled 1,3-dipolar cycloaddition for the diastereoselective synthesis of either syn- or anti-imidazolines. This method provides scaffolds with four points of diversity and control over two stereocenters.
ASYMMETRIC SYNTHESIS OF AMINO ACIDS VIA THE CATALYTIC REDUCTION OF ACYLAMINOACRYLIC ACID AZLACTONE DERIVATIVES. 24. REDUCTIVE AMINOLYSIS OF 2-METHYL-4-BENZYLIDENE-Δ2-OXAZOLIN-5-ONE UPON TREATMENT WITH A CATALYTIC SYSTEM BASED ON S-PHENYLALANINE DERIVATIVES
Lyubeznova, M. R.,Karpeiskaya, E. I.,Klabunovskii, E. I.
, p. 720 - 726 (2007/10/02)
Reductive aminolysis of 2-methyl-4-benzylidene-Δ2-oxazolin-5-one upon treatment with a PdCl2-S-phenylalanine ester (dimethylamide) catalytic system leads to the formation of the corresponding acylated dipeptide derivatives, with the R,S-configuration (diastereomer) predominating (DE 9-27percent).The reaction stereoselectivity in dimethoxyethane increases sharply in the presence of triethylamine additive, and in the case of S-phenylalanine methyl ester reaches 47percent.The stepwise mechanism for this process has been studied.
ASYMMETRIC SYNTHESIS OF AMINO ACIDS VIA THE CATALYTIC REDUCTION OF SUBSTITUTED ACYLAMINOACRYLIC ACID AZLACTONE DERIVATIVES. 25. REDUCTIVE AMINOLYSIS OF 2-PHENYL- AND 2-METHYL-Δ2-OXAZOLIN-5-ONES UPON TREATMENT WITH A CHIRAL PdCl2-R-PHENYLGLYCINE
Chel'tsova, G. V.,Karpeiskaya, E. I.,Klabunovskii, E. I.
, p. 727 - 731 (2007/10/02)
We have studied the reaction of Δ2-oxazolin-5-ones with R-phenylglycine methyl ester in the presence of PdCl2; the reaction gives phenylalanine or valine dipeptide derivatives with the RS-configuration.The presence of triethylamine during the r
ASYMMETRIC SYNTHESIS OF AMINO ACIDS VIA THE CATALYTIC REDUCTION OF SUBSTITUTED ACYLAMINOACRYLIC ACID AZLACTONES. 26. AMINOLYSIS OF 2-METHYL-4-BENZYLOXAZOLIN-5-ONE UPON REACTION WITH S-PHENYLALANINE DERIVATIVES
Lyubeznova, M. R.,Karpeiskaya, E. I.,Klabunovskii, E. I.,Koreshkov, Yu. D.,Lutsenko, A. I.,Lubuzh, E. D.
, p. 731 - 737 (2007/10/02)
The kinetics of aminolysis and racemization of 2-methyl-4-benzyloxazolin-5-one upon reaction with S-phenylalanine methyl ester have been studied in dimethoxyethane solvent.The rates of aminolysis and racemization are comparable.Addition of an achiral component, namely Et3N, to the reaction mixture, however, dramatically increases the rate of racemization.The presence of Et3N also increases the ratio of rate constants for the formation of RS- and SS-diastereomers, which determines the reaction stereoselectivity.
Intramolecular Participation by a Neighboring Amide Group in the Hydrolysis of N-Acylimidazoles
Kogan, Robert L.,Fife, Thomas H.
, p. 5229 - 5232 (2007/10/02)
Rate constants have been determined for the disappearance of the N-acylimidazole derivatives of N-acetylphenylalanine and N-acetylvaline in H2O at 30 deg C.The pH-rate constant profiles are characterized by large pH-independent regions.These reactions are
