930769-47-4Relevant academic research and scientific papers
RETRACTED ARTICLE: Site-selective enzymatic C-H amidation for synthesis of diverse lactams
Cho, Inha,Jia, Zhi-Jun,Arnold, Frances H.
, p. 575 - 578 (2019/06/07)
A major challenge in carbon?hydrogen (C?H) bond functionalization is to have the catalyst control precisely where a reaction takes place. In this study, we report engineered cytochrome P450 enzymes that perform unprecedented enantioselective C?H amidation reactions and control the site selectivity to divergently construct b-, g-, and d-lactams, completely overruling the inherent reactivities of the C?H bonds. The enzymes, expressed in Escherichia coli cells, accomplish this abiological carbon?nitrogen bond formation via reactive iron-bound carbonyl nitrenes generated from nature-inspired acyl-protected hydroxamate precursors. This transformation is exceptionally efficient (up to 1,020,000 total turnovers) and selective (up to 25:1 regioselectivity and 97%, please refer to compound 2v enantiomeric excess), and can be performed easily on preparative scale.
HPLC enantioseparation on a homochiral MOF-silica composite as a novel chiral stationary phase
Tanaka, Koichi,Muraoka, Toshihide,Otubo, Yasuhiro,Takahashi, Hiroki,Ohnishi, Atsushi
, p. 21293 - 21301 (2016/03/08)
The last frontier in the development of chiral stationary phases for chromatographic enantioseparation involves homochiral metal-organic frameworks (MOFs). Using enantiopure (R)-2,2′-dihydroxy-1,1′-binaphthalene-6,6′-dicarboxylic acid as a starting material, we prepared three homochiral MOFs that were further used as chiral stationary phases for high-performance liquid chromatography to separate the enantiomers of various kinds of racemic sulfoxides, sec-alcohols, β-lactams, benzoins, flavanones and epoxides. The experimental results showed excellent performances for enantioseparation, and highlighted that enantioseparation on homochiral MOF columns is practical.
Catalytic, enantioselective N-acylation of lactams and thiolactams using amidine-based catalysts
Yang, Xing,Bumbu, Valentina D.,Liu, Peng,Li, Ximin,Jiang, Hui,Uffman, Eric W.,Guo, Lei,Zhang, Wei,Jiang, Xuntian,Houk,Birman, Vladimir B.
supporting information, p. 17605 - 17612 (2013/01/15)
In contrast to alcohols and amines, racemic lactams and thiolactams cannot be resolved directly via enzymatic acylation or classical resolution. Asymmetric N-acylation promoted by amidine-based catalysts, particularly Cl-PIQ 2 and BTM 3, provides a convenient method for the kinetic resolution of these valuable compounds and often achieves excellent levels of enantioselectivity in this process. Density functional theory calculations indicate that the reaction occurs via N-acylation of the lactim tautomer and that cation-π interactions play a key role in the chiral recognition of lactam substrates.
Kinetic resolution of β-lactams via enantioselective N-acylation
Yang, Xing,Bumbu, Valentina D.,Birman, Vladimir B.
experimental part, p. 4755 - 4757 (2011/11/04)
Enantioselective N-acylation of 4-aryl-β-lactams in the presence of acyl transfer catalyst Cl-PIQ provides an effective method for their non-enzymatic kinetic resolution.
A new route to enantiopure β-aryl-substituted β-amino acids and 4-aryl-substituted β-lactams through lipase-catalyzed enantioselective ring cleavage of β-lactams
Forro, Eniko,Paal, Tihamer,Tasnadi, Gabor,Fueloep, Ferenc
, p. 917 - 923 (2007/10/03)
A simple and efficient direct enzymatic method was developed for the synthesis of 4-aryl-substituted β-lactams and the corresponding β-amino acid enantiomers through the CAL-B (lipase B from Candida antarctica)-catalyzed enantioselective (E > 200) ring cleavage of the corresponding racemic β-lactams with 1 equiv. of H2O in i-Pr2O at 60°C. The product (R)-β-amino acids (ee ≥ 98%, yields ≥ 42%) and unreacted (S)-β-lactams (ee ≥ 95%, yields ≥ 41%) could be easily separated. The ring opening of enantiomeric β-lactams with 18% HCl afforded the corresponding enantiopure β-amino acid hydrochlorides (ee ≥ 99%).
